Large Bulk (RE)BCO superconducting magnets for desktop NMR/MRI
Lead Research Organisation:
University of Cambridge
Department Name: Engineering
Abstract
NMR and MRI are techniques that use the interactions of atoms with external magnetic fields to look inside materials, objects and organisms to study their composition (NMR) and provide images (MRI). They are used very widely in scientific research, medical research and in industry and medicine. Put simply, the stronger the magnetic field available the better these techniques work. Unfortunately, obtaining large magnetic fields (typically 20 -30 times strong than a fridge magnet) generally requires expensive magnets, which are usually wound from long lengths of superconducting wire. It would be ideal to be able to produce these very large magnetic fields in a much simpler fashion to provide convenient and cheap desktop systems. Making these systems widely available and cheaper would allow more scientists, engineers and medical researchers to have access to this equipment, and to use it more often. The importance of this proposed project is underlined by the active participation and practical help offered by our three industrial partners.
We are proposing to use ceramic bulk (in disc- or ring-form) superconductors, rather than complex solenoidal coils made from superconducting wire. The three main challenges that must be overcome to do achieve this are (i) making bulk superconductors of sufficient size and uniformity, (ii) making the magnetic field they produce highly uniform, and (iii) developing a practical way of charging bulks samples with magnetic field. To address the first two challenges the Cambridge group, with extensive experience of the fabrication and manufacture of these bulk superconductors, is going to partner with the Oxford group, who have experience of using advanced microscopy to look carefully at the fine details of the manufacturing process. To magnetise the bulk superconductors, we propose to discharge, over a period of several milliseconds, the energy stored in a bank of capacitors into a conventional coil magnet made of copper. Such a copper coil would overheat and melt if were to generate a large magnetic field continuously. However, using this pulsed field magnetisation technique, we can achieve the required field over a short period of time, but long enough to allow the bulk superconductor to "capture" the magnetic field.
We will consider the project successful if we can replace the conventional, permanent magnet of an existing NMR system, provided by our industrial partner, with our prototype bulk superconductor based system and demonstrate that it operates effectively at the proton resonance frequency of 200 MHz, rather than at 90 MHz, which is typical of existing permanent magnet systems and a limiting feature of this technology.
We are proposing to use ceramic bulk (in disc- or ring-form) superconductors, rather than complex solenoidal coils made from superconducting wire. The three main challenges that must be overcome to do achieve this are (i) making bulk superconductors of sufficient size and uniformity, (ii) making the magnetic field they produce highly uniform, and (iii) developing a practical way of charging bulks samples with magnetic field. To address the first two challenges the Cambridge group, with extensive experience of the fabrication and manufacture of these bulk superconductors, is going to partner with the Oxford group, who have experience of using advanced microscopy to look carefully at the fine details of the manufacturing process. To magnetise the bulk superconductors, we propose to discharge, over a period of several milliseconds, the energy stored in a bank of capacitors into a conventional coil magnet made of copper. Such a copper coil would overheat and melt if were to generate a large magnetic field continuously. However, using this pulsed field magnetisation technique, we can achieve the required field over a short period of time, but long enough to allow the bulk superconductor to "capture" the magnetic field.
We will consider the project successful if we can replace the conventional, permanent magnet of an existing NMR system, provided by our industrial partner, with our prototype bulk superconductor based system and demonstrate that it operates effectively at the proton resonance frequency of 200 MHz, rather than at 90 MHz, which is typical of existing permanent magnet systems and a limiting feature of this technology.
Planned Impact
The aim of this project is to lay the foundation to open up a whole new market segment for desktop MRI and NMR systems utilising magnetic fields of up to 5 T. Existing systems either use large and bulky room size superconducting solenoids and are expensive (>£1m) or sacrifice performance by employing much cheaper permanent magnets [1]. Our project would therefore make a direct and positive economic contribution in a field where UK companies, including Oxford Instruments and Siemens Healthineers, both of which are partners in this project, are sector leaders [2]. The NMR market has been predicted to reach over $2.5 billion by the mid 2020s [3] and that of the MRI market $5 billion [4].
Reducing the cost and size of these instruments will have a broader societal impact, making the technology, as well as the analysis, more affordable for end-users. In addition, the increased field offered by bulk superconducting magnets will allow improvements in performance, from 40-90 MHz typical of permanent magnet systems [5] to 200 MHz, increasing throughput and widening the range of applications for these cheaper systems.
Our proposal has been developed with companies that make systems using these technologies. This means they will be able to advise us at every stage of the project to make sure that our focus is relevant to the ultimate exploitation of the technology. This also means that, if successful, there will be a clear route from laboratory to factory for the progress we demonstrate.
This project targets a bore size suitable for research, rather than medical diagnostic work. Nonetheless, if we successfully overcome the limitations of sample size, solenoids based on bulk superconductors could find a role in Extremity MRI [6]. These are compact systems that reduce the load on expensive full size systems by providing imaging of limbs. This is of increasing importance as MRI becomes a more heavily used technique, in the NHS there has been an over 200% increase in demand over a 10-year period [7].
The availability of larger, high quality, bulk superconductors that we propose to develop would benefit the wide range of potential applications for bulk superconductors. Those identified, besides NMR and MRI , in our recently published roadmap for the application of bulk superconductors[8] include compact high power density motors for electric aircraft and road transport, large magnetic fields for drug targeting and magnetic shielding systems.
[1] https://lbnmedical.com/how-much-does-an-mri-machine-cost/
[2] Melhem Z 2011 Materials UK Prelim. Review, Superconducting Materials and Applications: A UK Challenge and an Opportunity
[3] https://www.reuters.com/brandfeatures/venture-capital/article?id=78610
[4] https://www.reuters.com/brandfeatures/venture-capital/article?id=104390
[5] http://www.magritek.com/products/spinsolve/
[6] https://www.gehealthcare.com/news-center/optima-mr430s-scanner
[7] https://www.england.nhs.uk/statistics/
[8] Durrell et al., Superconductor Science and Technology, Volume 31, Number 1
Reducing the cost and size of these instruments will have a broader societal impact, making the technology, as well as the analysis, more affordable for end-users. In addition, the increased field offered by bulk superconducting magnets will allow improvements in performance, from 40-90 MHz typical of permanent magnet systems [5] to 200 MHz, increasing throughput and widening the range of applications for these cheaper systems.
Our proposal has been developed with companies that make systems using these technologies. This means they will be able to advise us at every stage of the project to make sure that our focus is relevant to the ultimate exploitation of the technology. This also means that, if successful, there will be a clear route from laboratory to factory for the progress we demonstrate.
This project targets a bore size suitable for research, rather than medical diagnostic work. Nonetheless, if we successfully overcome the limitations of sample size, solenoids based on bulk superconductors could find a role in Extremity MRI [6]. These are compact systems that reduce the load on expensive full size systems by providing imaging of limbs. This is of increasing importance as MRI becomes a more heavily used technique, in the NHS there has been an over 200% increase in demand over a 10-year period [7].
The availability of larger, high quality, bulk superconductors that we propose to develop would benefit the wide range of potential applications for bulk superconductors. Those identified, besides NMR and MRI , in our recently published roadmap for the application of bulk superconductors[8] include compact high power density motors for electric aircraft and road transport, large magnetic fields for drug targeting and magnetic shielding systems.
[1] https://lbnmedical.com/how-much-does-an-mri-machine-cost/
[2] Melhem Z 2011 Materials UK Prelim. Review, Superconducting Materials and Applications: A UK Challenge and an Opportunity
[3] https://www.reuters.com/brandfeatures/venture-capital/article?id=78610
[4] https://www.reuters.com/brandfeatures/venture-capital/article?id=104390
[5] http://www.magritek.com/products/spinsolve/
[6] https://www.gehealthcare.com/news-center/optima-mr430s-scanner
[7] https://www.england.nhs.uk/statistics/
[8] Durrell et al., Superconductor Science and Technology, Volume 31, Number 1
Publications
Tsui Y
(2022)
Portable, desktop high-field magnet systems using bulk, single-grain RE-Ba-Cu-O high-temperature superconductors
in Superconductor Science and Technology
Congreve J
(2024)
Optimisation of the processing parameters for the fabrication of high-quality joints between Y-Ba-Cu-O single grain, bulk superconductors
in Superconductor Science and Technology
Shi Y
(2023)
Optimisation of stacked, bulk high temperature superconductors for trapped-field magnet applications
in Superconductor Science and Technology
Gao Z
(2024)
Microstructure of superconducting hetero-joints between single-grained Gd-Ba-Cu-O bulk superconductors
in Superconductor Science and Technology
Huang K
(2021)
Improved trapped field performance of single grain Y-Ba-Cu-O bulk superconductors containing artificial holes
in Journal of the American Ceramic Society
Namburi D
(2021)
Improved mechanical properties through recycling of Y-Ba-Cu-O bulk superconductors
in Journal of the European Ceramic Society
| Description | Due to the Covid-2019, there has been limited access to the lab in 2020-21, which means only 60% of the work has been completed. 1. A study on the stacking of two single grains exhibiting different trapped fields at their top and bottom surfaces has been performed and completed. The results show that the best high and most uniform trapped field of the stack of two samples is achieved by placing the two bottom surfaces (which are usually those with lower and non-uniform trapped fields) in intimate contact in the middle of the stack. 2. A further improved and stabilised the melt process has been developed. This process involves wet-ball mixing to increase the uniformity of the mixed precursor powder to improve the reliability of the crystal growth and uniformity of the superconductivity within the bulk single grains. 3. A method that allows the growth of ring-shaped single grains directly has been developed to improve the uniformity of the superconducting properties. 4. The superconducting properties of single grains containing different rare-earth elements (Gd and Eu), different sources of supply and the effects of the Ag addition has been investigated. The results show that adding Ag improves the superconducting properties of the single grain, including the trapped field, despite the fact that Ag is not superconducting. Research in this area is continuing. 5. Multi pulse-magnetisation of a relatively large numbers of bulk and ring samples has been used to demonstrate there is no clear correlation between the trapped field obtained by field-cooling by pulse-magnetisation. The thermal conductivity of the assembled composite single grain, however, is most likely a dominating factor in determining the final trapped field. 6. The intrinsic uniformity of the superconducting properties of single grain (RE)BCO materials has been further studied. For the first time, the distribution of the Jc-B at a facet line has been measured and compared with the distribution of Jc-B in the a/b direction. In general, and significantly, the facet lines exhibit higher Jc-B. 7. A variety of shapes of bulk, single grain material, such as cylinders, rings 41OD16ID (8 of 10), square and triangular geometries have been fabricated successfully. The work for assembling the samples for designs A and B in the proposal is in progress. 8. GdBCOAg single grains up to 60 mm in diameter have been grown for the first time. 9. EuBCOAg single grains up to 60 mm in diameter have been grown for the first time. The Eu/Ba substitution issue in the EuBCO system has been resolved and the BaO2 content optimised for suppressing the Eu/Ba substitution to improve the trapped field. 10. Detailed research on the distribution of the critical supercurrent density (Jc) of single grains has been performed. A comparison of Jc at the facet line and along the a/b direction over the entire ac-plane has been made and the effect of the observed difference in the trapped field contour map examined. 11. It has been confirmed that the distributions of Jc do not correlate directly with volume fraction of Gd-211 phase content, suggesting for the first time that Gd-211 may not be the main factor determining Jc. 12. An arrangement has been proposed to reduce the effect of the changing Jc distribution along the facet lines to provide a more uniform trapped field, which may inspire future research directions. 13. The microstructure and superconducting properties of EuBaCuO and GdBaCuO single grain samples have been compared and a paper has been published. 14. Systematic PFM measurements on a Gd-Ba-Cu-O ring bulk sample have been carried out and a trapped field of 1.3 T at 55 K has been achieved using a multi-pulse, step-wise cooling (MPSC) technique (a paper has been published). The MPSC technique is repeatable and helps to avoid catastrophic flux jumps that can occur during the PFM of bulk ring that reduce significantly the trapped field and/or interrupt the circulating supercurrent. 15. 6 GdBCOAg and EuBCOAg single grains of diameter 60 mm have been fabricated successfully as required for the field pulse tests (one sample was broken during the mounting process). 16. After confirming that RE-211 sometimes may not be the main factor determining Jc, the effect of porosity on Jc has also been investigated by examining statistically 25 YBCO single grains of different sizes, suggesting for the first time that there is a strong correlation between the average Jc and porosity. 17. The effect of differences in Jc along the facet lines and the a/b direction has been studied mainly in terms of the shape of trapped field. Published results confirmed that the top surface of single grains tend to produce non-uniform square-shaped trapped field contour maps. However, circular contour maps can be achieved by stacking single grains with their facet lines off-set by 45 degrees. This research also suggests that a more uniform trapped field can be achieved by assembling samples in an appropriate arrangement, which has led, in turn, to the concept of "housing". 18. A multi-pulse step-wise-cooling (MPSC) sequence that includes a longer first-pulse rise time and multiple pulses of the same magnitude for some steps has been developed to achieve a trapped field of 1.3 T at 55 K. This is about four times that of the highest trapped field reported for any single ring bulk single grain sampel magnetised using PFM to date and represents a promising step forward in magnetising bulk, single-grain superconducting rings for use in practical engineering applications. 19. The magnitisation processes of single grains rings are better understood both analytically and experimentally as a result of this research. Magnetic flux is found to penetrate finite-thickness HTS rings from both the inner and outer surfaces, inducing a negative field at the inner face of the ring. As the applied field increases past the point of full penetration, the field at the inner surface is reversed, causing significant heating of the sample around this location. This makes HTS rings significantly more susceptible to localised heating and thermomagnetic instabilities that limit severely their ability to trap a useful magnetic field. In some cases, this can result in breaking the supercurrent flowing around the ring related to the HTS ring magnetisation, and a negative trapped field in the ring bore. Consequently, thermomagnetic stability of HTS rings during typical single-pulse PFM can only be ensured by applying a magnetising field that does not fully penetrate the sample, or by using more advanced PFM techniques like waveform control or multi-pulse stepwise-cooling to increase the trapped field. |
| Exploitation Route | The results of the study on the stacking of two single grains will help the scientific community understand the use of one type of an assembly of single grains. The improved trapped field obtained and uniformity in the resultant composite bulk compared to a monolithic bulk superconductor of the same diameter will help design the assemblies for bespoke, high field applications. The processing technique developed to allow the growth of ring-shape single grains directly what the potential to save materials and improve superconducting properties (more analysis is being performed). An arrangement has been proposed to reduce the effect of changing Jc distribution and provide a more uniform trapped field, which has direct implications for practical applications and may inspire future research directions. Further understanding on achieving uniform trapped field has triggered a "housing" idea, e.g. placing the object that is needed to provide uniform filed in applications in a "house" like assembly of smaller single grains to obtaining higher and more uniform magnetic field. The idea may attract interest from industry. |
| Sectors | Energy Healthcare Transport |
| Description | Detailed research on 20 specimens of half cross-section of a GdBCO single grain have shown that Jc-B at 77 K of these samples measured along facet line is about 10% higher than that in a/b direction (intrinsic compositional and structural differences along a facet line and the a/b direction is the reason for different Jc behaviour). As a result, trapped fields measured at the top layers of fully grown, high quality single grains exhibit squarer cross-sections, which is not generally desirable in practical applications. A sample arrangement has been proposed that reduces the effect of the variation in Jc distribution to provide a more uniform trapped field across the entire sample cross-section. This has been achieved by stacking two single grain slices with square-shaped trapped field contour maps in different orientations resulting in a uniform circular trapped field, demonstrating that it is possible to achieve a uniform trapped field from non-uniform material with non-uniform Jc. This observation may be used ultimately to achieve higher and more uniform fields in applications, such as MRI/NMR, levitation and undulators by the careful arrangement of individual single grains in an assembly. Further understanding on achieving uniform trapped field triggered a "housing" idea, e.g. placing the object that is needed to provide uniform magnetic field in applications in a "house-like" assembly of smaller single grains to obtain a higher and more uniform magnetic field. The idea is innovative and may attract interest from industry and initiate new research activity. After confirming that RE-211 may not always be the main factor determining Jc, the effect of porosity on Jc was also performed by examining statistically 25 YBCO single grains of different sizes, suggesting for the first time that there is a strong correlation between the average measured Jc and porosity. This observation suggests that any method that reduces porosity would improve the average Jc and hence trapped field. Although reducing porosity is limited to some extent, the relevant methods and processing techniques should be explored further and improved. The magnitisation processes of single grain rings are better understood both analytically and experimentally as a direct result of this research. Magnetic flux is found to penetrate finite-thickness HTS rings from both the inner and outer surfaces, inducing a negative field at the inner face of the ring. As the applied field increases past the point of full penetration, the field at the inner surface is reversed, causing significant heating of the sample around this location. This makes single grain HTS rings significantly more susceptible to localised heating and thermomagnetic instability that limit severely their ability to trap a useful magnetic field. This observation aids significantly the understanding of the pulse magnitisation of ring-shaped single grains, which is particularly important for NMR/MRI applications. |
| First Year Of Impact | 2020 |
| Sector | Energy,Transport |
| Impact Types | Societal |
| Title | A reliable technique to fabricate superconducting joints between single grain, Y-Ba-Cu-O bulk superconductors dataset |
| Description | This contains trapped field data and trapped field profiles associated with a paper submission on joining of bulk superconductors. The trapped field profiles were measured using a rotating hall probe array at a distance approximately 1.5 mm from the surface of the bulk superconductor. The samples were zero field cooled to 77 K with a field of 1.4 T. Samples were maintained at a temperature of 77 K for the duration of the measurements. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2021 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/329344 |
| Title | Dataset for 'Improved trapped field performance of single grain Y-Ba-Cu-O bulk superconductors containing artificial holes' |
| Description | Dataset accompanying the paper entitled 'Improved trapped field performance of single grain Y-Ba-Cu-O bulk superconductors containing artificial holes', which measured the tensile strength of standard and thin-wall (i.e., with artificial holes) YBCO samples then subsequently confirmed the effect of the strength improvement on the trapped field capability of the different sample types. The dataset contains results obtained using the following techniques: (i) the Brazilian test to measure tensile strength of cylindrical samples, (ii) optical microscopy to measure sample porosity and (iii) a 12-tesla high-field magnet to magnetise and break the samples when they were superconducting. Explanations of figures containing experimental results: Fig. 3b shows the ramp rates used to magnetize the samples. The rates were fixed for each field range. Fig. 4 shows the strength of various sample types (i.e. standard, thin-wall) measured using the Brazilian test. Fig. 5a shows the optical images taken at half height across each sample, and Fig. 5b shows the porosity analysis on these images using ImageJ software. Fig. 6a and 6b show the performance of the two sample types, i.e. field trapped by the sample as a function of the applied field, showing where the sample failed. The samples were magnetized using the 12-tesla magnet. Fig. 7b shows the 2D field profile measured on the surface of the thin-wall sample using an array of hall sensors. Fig. 8 shows the field measured along the diameter of the thin-wall sample when magnetised using 11 T at 30 K. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2021 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/325383 |
| Title | Microstructure of superconducting hetero-joints between single-grained Gd-Ba-Cu-O bulk superconductors |
| Description | EDX, DTA and trapped field data on GdBCO/YBCO/GdBCO jointed bulks fabricated by Cambridge University Engineering Department |
| Type Of Material | Database/Collection of data |
| Year Produced | 2024 |
| Provided To Others? | Yes |
| URL | https://ora.ox.ac.uk/objects/uuid:7425ce4d-6a99-4353-ac3b-cd9643c5eeb5 |
| Title | Research Data supporting "A Route to Fabricate Low Resistance Joints between Eu-Ba-Cu-O Bulk Superconductors dataset" |
| Description | In this study samples of single-grained Eu-Ba-Cu-O-Ag were joined using intermediate slices of Y-Ba-Cu-O-Ag. The term 'parent' refers to the original sample before cutting and joining, the term 'joined' refers to the sample after joining. The trapped field measurements in this dataset were taken at surface sing a hand-held Hall probe positioned 0.5 mm above the sample surface. The samples had been field cooled to 77 K in an applied magnetic field of 1.4 T prior to trapped field measurement. The temperature of each sample was maintained at 77 K for the duration of the trapped field measurement. To observe the microstructure the samples were cut in half perpendicular to the joining material and the surface was then polished. The samples were imaged using a scanning electron microscope (SEM) operating at 20 kV using 100x magnification at 1 mm intervals in the c-axis direction in the vicinity of the interface of the join. Further images were taken at 1000x magnification at the join interface and at 2 mm intervals along the c-axis direction within the joining intermediate material. The composition of an area of approximately 140 µm by 100 µm at each of the locations imaged at 1000x magnification within the joining intermediate material were analysed using energy-dispersive x- ray analysis (EDAX) to observe the variation in the distribution of silver, yttrium, barium and copper in the sample microstructure. These data have been normalised to exclude variations in oxygen content within the area analysed (i.e. the sum of the weight percentages of Ag, Y, Ba and Cu has been set equal to 1). |
| Type Of Material | Database/Collection of data |
| Year Produced | 2024 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/372428 |
| Title | Research Data supporting "A detailed comparison of (RE)-Ba-Cu-O bulk superconductors dataset" |
| Description | This contains detailed compositition data from the locations described in the publication. Abstract of related publication: The homogeneity of the microstructure and composition are critical in determining the properties of rare earth-barium-cuprate, single grain bulk superconductors [(RE)BCO]. The magnitude of the trapped magnetic field achieveable in these technologically important materials, in particular, is influenced heavily by the size and distribution of (RE)2BaCuOx (RE-211) flux pinning inclusions in the bulk microstructure, whereas the size and distribution of silver agglomerates present within the bulk superconducting matrix correlate directly with improved mechanical properties. With careful engineering, these materials have significant potential for application in range of devices related to energy storage, medicine, electro-magnetic machinery and microelectronic technology. Fabrication of (RE)BCO bulk superconductors typically involves heating a powder compact above its peritectic decomposition temperature followed by slow cooling to facilitate the growth of a single grain. Each (RE)BCO composition has a different peritectic temperature and growth rate, which, therefore, necessitates different requirements in the heating profile. The fabrication temperature and growth rate, for example, may have an effect on the RE-211 and silver distribution, which may, in turn, affect the superconducting properties of the resulting single grain. In this work we compare the distributions of silver and RE-211 in the single grain microstructures of YBCO-Ag, GdBCO-Ag, EuBCO-Ag and SmBCO-Ag bulk superconductors using optical microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. We observe that the distributions are very similar along both the a/b-axis and c-axis of these materials. This suggests that factors other than the maximum temperature used to achieve peritectic decomposition and the rate of single grain growth are particularly influential in determining the properties of the as-processed samples in the top seeded melt growth process. This observation demonstrates there is freedom to use (RE) materials interchangeably between different applications as required, for example, for functional or economic reasons. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2024 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/364768 |
| Title | Research Data supporting "Optimisation of the processing parameters for fabricating high-quality joints between Y-Ba-Cu-O bulk superconductors dataset" |
| Description | A dataset associated with the listed publication. Trapped field measurements taken as follows: The top and bottom faces of all of the YBCO samples were polished flat and parallel using 180 grit silicon carbide paper. The maximum trapped field at the top and bottom surface was measured initially using a hand-held Hall probe positioned approximately 0.5 mm above the sample surface. Subsequently, the trapped field profile across both the top and bottom surface of each single grain was measured using a rotating array of 19 Hall probes positioned approximately 1.5 mm above the surface of each sample. The samples had been field cooled at 77 K in an applied magnetic field of 1.4 T prior to trapped field measurement. The temperature of each sample was maintained at 77 K for the duration of each measurement. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2024 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/363188 |
| Title | Research Data supporting "Statistical evaluation of the mechanical and flux trapping properties of standard and thin-wall EuBCO(Ag) bulk superconductors" |
| Description | This dataset contains supporting information for the journal article "Statistical evaluation of the mechanical and flux trapping properties of standard and thin-wall EuBCO(Ag) bulk superconductors". The file "README.txt" contains detailed information about the data measurement and evaluation. The file "Raw_data.xlsx" contains the raw data used for the plots illustrated in figures 3,4 and 6. The file "Determination_Weibull_modulus.xlsx" explains the calculation of the Weibull modulus for EuBCO(Ag), thin wall EuBCO(Ag) and Stycast filled thin wall EuBCO(Ag) bulk materials. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/358361 |
| Title | Research Data supporting "Statistical evaluation of the mechanical properties of partially oxygenated YBCO, oxygenated YBCO and oxygenated YBCO(Ag) single grains" |
| Description | This dataset contains supporting information for the journal article "Statistical evaluation of the mechanical properties of partially oxygenated YBCO, oxygenated YBCO and oxygenated YBCO(Ag) single grains". The file "README.txt" contains detailed information about the data measurement and evaluation. The file "Raw_data.xlsx" contains the raw data used for the plots illustrated in figures 4, 5 and 7. The file "calculation_weibull_modulus.xlsx" explains the calculation of the Weibull modulus. The folders "Figure_4.zip" and "Figure_5.zip" contain the EDX maps and optical tracking microscope images used to gather the data for figures 4 and 5. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/352961 |
| Title | Research Data supporting "Statistical evaluation of the mechanical properties of partially oxygenated YBCO, oxygenated YBCO and oxygenated YBCO(Ag) single grains" |
| Description | This dataset contains supporting information for the journal article "Statistical evaluation of the mechanical properties of partially oxygenated YBCO, oxygenated YBCO and oxygenated YBCO(Ag) single grains". The file "README.txt" contains detailed information about the data measurement and evaluation. The file "Raw_data.xlsx" contains the raw data used for the plots illustrated in figures 4, 5, 7, 8 and 10. The file "calculation_weibull_modulus.xlsx" explains the calculation of the Weibull modulus for partially oxygenated YBCO, oxygenated YBCO and oxygenated YBCO(Ag) bulk materials. The folders "Figure_7.zip" and "Figure_8.zip" contain the EDX maps and optical tracking microscope images used to gather the data for figures 7 and 8. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/352961.2 |
| Title | Research Data supporting "Understanding the porosity and its effects on the superconducting properties of YBCO single grains" |
| Description | This dataset contains the raw data for the journal article "Understanding the porosity and its effects on the superconducting properties of YBCO single grains". The file "README.txt" contains detailed information about the measurement of the raw data and the determination of the data shown in the paper. The .tif files contain tracking microscope images (OLYMPUS BX51M) of all 22 investigated YBCO bulk superconductors (5x 13.6 mm, 5x 16.0 mm, 5x 20.8 mm, 4x 24.8 mm, 2x 30.7 mm, and 1x 41.8 mm diameter). The file "Raw_data.xlsx" contains the sample number, diameter, height, area, pore count, average pore size and porosity of each of the 22 samples investigated. Furthermore, the file contains the maximum/minimum trapped field measured at the top and bottom of each sample. The average critical current density at the top/bottom of each sample was calculated with the formula shown in Equation 4 in the paper. Furthermore, "Raw_data.xlsx" contains the pore sizes measured for each sample set (Figure 6 in publication). The file "Raw_data_trapped_field.xlsx" contains the raw data for the trapped field profiles measured with 18 rotating hall probes 1.5 mm above the sample surface at 77 K (Figure 3 in publication). |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/343120 |
| Title | Research data supporting "Dynamics of Magnetic Flux Propagation in Bulk, Single Grain Superconducting Rings during Pulsed Field Magnetisation" |
| Description | A summary of the research data supporting "Dynamics of Magnetic Flux Propagation in Bulk, Single Grain Superconducting Rings during Pulsed Field Magnetisation" The corresponding files contain the supplementary data for the paper DOI: - Modelling_Data.xlsx - Experimental_Data.xlsx - Fig17_Bz_J-Q-T-export-15-17-19ms.txt - Fig17-J-Q-higherdensity-export-15-17-19ms.txt - Fig17-J-Q-export-17p5ms.txt Detailed information about each file can be found in the READ_ME.txt file. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/341253 |
| Title | Research data supporting "Fabrication of high-quality joints between Gd-Ba-Cu-O bulk superconductors" |
| Description | Data associated with publication of 'Fabrication of high-quality joints between Gd-Ba-Cu-O bulk superconductors.' Each of the files in this dataset is associated with measurement of the magnetic trapped field profile for samples pre and post-jointing. The trapped magnetic field profiles have been measured using a rotating Hall probe array which has 19 Hall probes attached. These have been measured after field cooling to 77 K in a 1.4 T magnetic field. The samples are maintained at 77 K throughout measurement and measurements are taken at zero external magnetic field. Sample labelling: 1=A1, 3=D1, 4=E1, 5=B1, 6=C1, 7=B2, 11=B3, 12=D2 and 13=B4. Sample reference numbers were changed to make the manuscript easier for the reader to follow. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/350598 |
| Title | Research data supporting "Optimisation of stacked, bulk high temperature superconductors for trapped-field magnet applications" |
| Description | The dataset of Figure 4(1), 4(2), 4(3), 4(4), 4(5) and 4(6) contains the raw data of the trapped measurement correspondent to Figure 4(1), 4(2), 4(3), 4(4), 4(5) and 4(6). The trapped fields were measured using a rotating array consisting of 18 Hall probes at 1.5 mm above the surface of the sample. The fields signals were sent and recorded by Origin 8.5 (or later version), then the Origin generates contour maps for indicating the distribution of the fields. In this study, we use the contour maps to present the uniformity of the trapped fields. The dataset of Figure 8 thickness3.5 and Figure 8 thickness1.5 contains the raw data of the modelling results presented using Origin in Figure 8(a) and (b) where the thickness of the sample with Jc-B(1) is 1.5 mm & Jc-B(2) is 8.5 mm and the thickness of the sample with Jc-B(1) is 3.5 mm & Jc-B(2) is 6.5 mm respectively. The datasets of Figure 9, figure 10 and Figure 11 contain the raw data of the modelling results. Origin 8.5 (or later version) was used to draw the curves in Figure 9, figure 10 and Figure 11. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/350953 |
| Title | Research data supporting "Portable, desktop high-field magnet systems using bulk, single-grain RE-Ba-Cu-O high-temperature superconductors" |
| Description | Research data supporting [Portable, desktop high-field magnet systems using bulk, single-grain RE-Ba-Cu-O high-temperature superconductors]. The Microsoft Excel file contains all data plotted in figures 1 to 8 except figure 2 in the main manuscript. Figure 2 is the schematic diagram of the experimental rigs. For all pulsed field magnetization data, the sample was first cooled down from the normal state to the superconducting state then a single pulsed field or a sequence of two pulsed fields (two-step multi-pulse) were applied to it. The values of trapped field shown in the data file are the values recorded at 15 seconds after applying each pulsed field. After reaching the set temperature the wait time before applying a magnetizing pulse was from was from ~5 min (at 77 K) to ~15 min (at 55 K) to allow sufficient time for the sample and the sample holder to reach the thermal equilibrium. Unless stated otherwise, the applied field and the trapped field were the peak value of the magnetizing pulse and the trapped field at the centre of the top surface of each sample, respectively. For the field cooling data, the sample was cooled from room temperature to 77 K, in an applied field of 1.5 T from a copper electromagnet, using a liquid nitrogen bath. The applied field was then removed and the trapped field profiles at 1.5 mm above the top surfaces of the sample were measured. A hand-held gaussmeter was also used to find the maximum trapped field on the surface of each sample. See the main manuscript for more details. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/337660 |
| Title | Research data supporting "The influence of porosity on the superconducting properties of Y-Ba-Cu-O single grains" |
| Description | This dataset contains the raw data for the journal article "The influence of porosity on the superconducting properties of Y-Ba-Cu-O single grains". The file "README.txt" contains detailed information about the measurement of the raw data and the determination of the data shown in the paper. The file "Raw_data.xlsx" contains raw data used to plot the graphs shown in Figures 4, 5, 6(a), 6(b), 7, 9, 11 and 12. The file "1373_25mm_YBCO_tracking_microscope.tif" contains the raw microscope image shown in Figure 3. The zip folders "1A-1H" contain image stacks of sample pieces 1A-1H measured using 3D X-ray Computer Tomography (XCT). Each zip folder also contains a header file with more details about the XCT measurements. The folder "SQUID" contains the raw data used to determine Tc, ?T90, and Jc measured using a Magnetic Properties Measurement System (MPMS). The folder "Optical_microscope" contains the raw images used to determine the Y-211 particle size and content. Furthermore, it also contains images where the Y-211 particles are marked in green and red, which were used to determine Y-211 size and content. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/352863 |
| Title | Research data supporting "Trapped Fields > 1 T in a Bulk Superconducting Ring by Pulsed Field Magnetization" |
| Description | Research data supporting [Trapped Fields > 1 T in a Bulk Superconducting Ring by Pulsed Field Magnetization]. The Microsoft Excel file contains all data plotted in figures 1 to 5 in the main manuscript. For all pulsed field magnetization data, the sample was first cooled down from the normal state to the superconducting state then a pulsed field or a sequence of pulsed field was applied to it. The values of trapped field shown in the data file are the values recorded at 15 seconds after applying each pulsed field. For a multi-pulse, stepwise cooling sequence, the wait time between two successive pulses was from ~5 min (at 77 K) to ~15 min (at 55 K) to allow sufficient time for the sample to return to its operating temperature before applying the next pulse. Unless stated otherwise, the applied field and the trapped field were the peak value of the magnetizing pulse and the trapped field at the centre of the sample bore, respectively. See the main manuscript for more details. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/335834 |
| Title | Research data supporting "Waveform Control Pulsed Field Magnetization of RE-Ba-Cu-O Bulk Superconducting Rings" |
| Description | Research data supporting [Waveform Control Pulsed Field Magnetization of RE-Ba-Cu-O Bulk Superconducting Rings]. The Microsoft Excel file contains all data plotted in figures 2 to 7 in the main manuscript. For the pulsed field magnetization data, the sample was first cooled down from the normal state to the superconducting state then a pulsed field was applied to it. The values of trapped field shown in the data file are the values recorded at 15 seconds after applying each pulsed field. For the field cooling data, the sample was cooled from room temperature to 77 K, in an applied field of 1.5 T from a copper electromagnet, using a liquid nitrogen bath. The applied field was then removed and the trapped field profiles at 1.5 mm above the top and bottom surfaces of the sample were measured. See the main manuscript for more details. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/336979 |
| Title | Research data supporting ''The effect of facet lines on critical current density and trapped field in bulk RE-Ba-Cu-O single grains'' |
| Description | Detailed current density measurements and the trapped fields measurements which show the effects of Jc distribution. Figure3 & Figure 4(a,c) (Tc and Jc along a faceline of sample 20181123 F7-1).xlsx are the results of critical transition temperature Tc and M-H loops measured using MPMS in the Maxwell centre. The critical current density Jc is calculated from the M-H loops for each cuboid at 77 K for an applied field cycle of 0 to 7 T to 0 T using the Bean model. All the data of 20 pieces of superconductor bulk samples in figure 1 is in this .xlsx file. The results are shown in figure 3 and 4. All .opj Origin 8.5 files are showing the measurements of trapped fields which are the indicators of samples' quality. We show the readers the shapes and magnitudes of trapped field for discussing ''The effect of facet lines on critical current density and trapped field in bulk RE-Ba-Cu-O single grains''. Each sample to be measured was field cooled at 77 K in an applied magnetic field of 1.0 T prior to 2D trapped field mapping using a rotating Hall sensor array. Origin was used to record the original data. These files here in .opj recorded the original data and their generated figures. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/339788 |
| Description | Can Superconductors |
| Organisation | Can Superconductors |
| Country | Czech Republic |
| Sector | Private |
| PI Contribution | The investigation of parallel processing techniques for bulk single grain superconductors. |
| Collaborator Contribution | Play the fundamental role in understanding the properties of performance of bulk superconductors fabricated from a variety of rare earth elements. |
| Impact | The development of an improved melt process for bulk superconductors that yields better trapped field and greater potential for engineering applications. |
| Start Year | 2006 |
| Description | Siemens |
| Organisation | Siemens AG |
| Department | Siemens plc, Keele |
| Country | United Kingdom |
| Sector | Private |
| PI Contribution | We provide samples for Siemens to do some measurements using their equipment. |
| Collaborator Contribution | Siemens is interested in the applications of bulk materials in motors. Our research results will provide better understanding. |
| Impact | multi-disciplinary |
| Start Year | 2016 |