Harnessing disorder to tune, tailor and design classical and quantum spin liquids
Lead Research Organisation:
University of Cambridge
Department Name: Physics
Abstract
Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.
Organisations
Publications
Chern L
(2022)
Competing quantum spin liquids, gauge fluctuations, and anisotropic interactions in a breathing pyrochlore lattice
in Physical Review B
De Tomasi G
(2022)
Effects of critical correlations on quantum percolation in two dimensions
De Tomasi G
(2022)
Effects of critical correlations on quantum percolation in two dimensions
De Tomasi G
(2022)
Effects of critical correlations on quantum percolation in two dimensions
in Physical Review B
| Description | (for the experimental part of the proposal, please see related reporting at RHUL and OXFORD) We gained a more in-depth understanding of the role of disorder in the form of oxygen deficiency in Ho-based pyrochlores. We characterised the effects at the microscopic, single-ion level. Characterisation of the macroscopic / collective behaviour is ongoing. We are in the process of modelling oxygen deficiencies as sources of local quantum dynamics, and we are trying to undersrtand how these affect the response, noise and equilibration properties of these systems. The aim will be to make prediction for experimentally measurable behaviour. We developed an understading of the nature of chemical composition disorder in Pr2ScNbO7. Comparison between theory and experiment allowed to understand the charge order / disorder in the distribution of Sc and Nb ions. This lead to crystallographic modelling and thence modelling of the magnetic properties of the Pr ions. Two different environments were identified, forming short quasi-1D chains. Preliminary results suggest that the one of the envoronments may be non-magnetic. Modelling of the resulting collective behaviour and furhter comparison with experiment is ongoing. We have put together a new computational approach based on single ion crystal electric field modelling and mean field approximation of the inter-atomic interactions to compute the magnetic response and susceptibility, in order to be able to compare with experiment. Theoretical work on magnetic correlations in spin ice materials lead to the discovery of an emergent fractal in a clean system, which solves a long standing puzzle in the out of equilibrium behaviour and magnetic noise of these systems. This work was further extended to consider out of equilibrium behaviour, and other ways to obtain emergent dynamical fractals, e.g., via longer range interactions. |
| Exploitation Route | The discovery of the emergent fractal is a seminal result that is receiving much attention in the news. It is of interest to a broad range of scientific communities. Moreover, the idea of significant slowing down and temporal scaling behaviour in materials that does not originate from disorder but rather from internal correlations that mimic a percolation process may have important implications for people working on spin ice materials and out of equilibrum phenomena and glassiness in general. We are progressing towards a generalised framework for the out of equilibrium properties as well as other avenues to produce similar behaviour in these systems. |
| Sectors | Education Other |
| Title | CSD 2128596: Experimental Crystal Structure Determination |
| Description | Related Article: Charlotte Pughe, Otto H. J. Mustonen, Alexandra S. Gibbs, Martin Etter, Cheng Liu, Sia^n E. Dutton, Aidan Friskney, Neil C. Hyatt, Gavin B. G. Stenning, Heather M. Mutch, Fiona C. Coomer, Edmund J. Cussen|2022|Inorg.Chem.|61|4033|doi:10.1021/acs.inorgchem.1c03655 |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.25505/fiz.icsd.cc29fzd4&sid=DataCite |
| Title | CSD 2128597: Experimental Crystal Structure Determination |
| Description | Related Article: Charlotte Pughe, Otto H. J. Mustonen, Alexandra S. Gibbs, Martin Etter, Cheng Liu, Sia^n E. Dutton, Aidan Friskney, Neil C. Hyatt, Gavin B. G. Stenning, Heather M. Mutch, Fiona C. Coomer, Edmund J. Cussen|2022|Inorg.Chem.|61|4033|doi:10.1021/acs.inorgchem.1c03655 |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.25505/fiz.icsd.cc29fzf5&sid=DataCite |
| Title | CSD 2128598: Experimental Crystal Structure Determination |
| Description | Related Article: Charlotte Pughe, Otto H. J. Mustonen, Alexandra S. Gibbs, Martin Etter, Cheng Liu, Sia^n E. Dutton, Aidan Friskney, Neil C. Hyatt, Gavin B. G. Stenning, Heather M. Mutch, Fiona C. Coomer, Edmund J. Cussen|2022|Inorg.Chem.|61|4033|doi:10.1021/acs.inorgchem.1c03655 |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.25505/fiz.icsd.cc29fzg6&sid=DataCite |
| Title | CSD 2128599: Experimental Crystal Structure Determination |
| Description | Related Article: Charlotte Pughe, Otto H. J. Mustonen, Alexandra S. Gibbs, Martin Etter, Cheng Liu, Sia^n E. Dutton, Aidan Friskney, Neil C. Hyatt, Gavin B. G. Stenning, Heather M. Mutch, Fiona C. Coomer, Edmund J. Cussen|2022|Inorg.Chem.|61|4033|doi:10.1021/acs.inorgchem.1c03655 |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.25505/fiz.icsd.cc29fzh7&sid=DataCite |
| Title | CSD 2128600: Experimental Crystal Structure Determination |
| Description | Related Article: Charlotte Pughe, Otto H. J. Mustonen, Alexandra S. Gibbs, Martin Etter, Cheng Liu, Sia^n E. Dutton, Aidan Friskney, Neil C. Hyatt, Gavin B. G. Stenning, Heather M. Mutch, Fiona C. Coomer, Edmund J. Cussen|2022|Inorg.Chem.|61|4033|doi:10.1021/acs.inorgchem.1c03655 |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.25505/fiz.icsd.cc29fzj8&sid=DataCite |
| Title | Data associated with "Free-spin dominated magnetocaloric effect in dense Gd3+ double perovskites" |
| Description | Data associated with the publication 'Free-spin dominated magnetocaloric effect in dense Gd3+ double perovskites.' Frustrated lanthanide oxides with dense magnetic lattices are of fundamental interest for their potential in cryogenic refrigeration due to a large ground state entropy and suppressed ordering temperatures, but can often be limited by short-range correlations. Here, we present examples of frustrated fcc oxides, Ba2GdSbO6 and Sr2GdSbO6 and the new site-disordered analog Ca2GdSbO6 ([CaGd]A[CaSb]BO6), in which the magnetocaloric effect is influenced by minimal superexchange (J1 ~ 10 mK). We report on the crystal structures using powder x-ray diffraction and the bulk magnetic properties through low-field susceptibility and isothermal magnetization measurements. The Gd compounds exhibit a magnetic entropy change of up to -15.8 J/K/molGd in a field of 7 T at 2 K, a 20% excess compared to the value of -13.0 J/K/molGd for a standard in magnetic refrigeration, Gd3Ga5O12. Heat capacity measurements indicate a lack of magnetic ordering down to 0.4 K for Ba2GdSbO6 and Sr2GdSbO6, suggesting cooling down through the liquid 4-He regime. A mean-field model is used to elucidate the role of primarily free spin behavior in the magnetocaloric performance of these compounds in comparison to other top-performing Gd-based oxides. The chemical flexibility of the double perovskites raises the possibility of further enhancement of the magnetocaloric effect in the Gd3+ fcc lattices. Please see readme file for details on contents of folders |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/337073 |
| Title | Data for Comparative study of magnetocaloric properties for Gd3+ compounds with different frustrated lattice geometries |
| Description | Data sets associated with the publication Comparative study of magnetocaloric properties for Gd3+ compounds with different frustrated lattice geometries Includes cif files obtained from X-ray diffraction analysis, magnetic and magnetocaloric data from magnetic susceptibility and isothermal magnetisation measurements and output from monte-carlo simulations. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/353937 |
| Title | Nuclear and magnetic diffraction study of monoclinic TbTaO4 |
| Description | |
| Type Of Material | Database/Collection of data |
| Year Produced | 2021 |
| Provided To Others? | Yes |
| URL | https://doi.ill.fr/10.5291/ILL-DATA.5-31-2854 |
| Title | Research data supporting "Crystal structure and specific heat of calcium lanthanide oxyborates Ca4LnO(BO3)3" |
| Description | Research data supporting the publication "Crystal structure and specific heat of calcium lanthanide oxyborates Ca4LnO(BO3)3". This project also formed part of Nicola Kelly's PhD research (2018-2022). Data collected includes powder X-ray diffraction (PXRD), powder neutron diffraction (PND), and heat capacity. Please see the file directory.txt for further details on the files. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/340890 |
| Title | Research data supporting "Magnetism on the stretched diamond lattice in lanthanide orthotantalates" |
| Description | Research data supporting the publication "Magnetism on the stretched diamond lattice in lanthanide orthotantalates". This project also formed part of Nicola Kelly's PhD research (2018-2022). Data collected includes powder X-ray diffraction (PXRD), powder neutron diffraction (PND), heat capacity, and magnetic susceptibility. Please see the file directory.txt for further details on the files. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/335874 |
| Title | Research data supporting Magnetic and magnetocaloric properties of the A2LnSbO6 lanthanide oxides on the frustrated fcc lattice |
| Description | Data from publication 'Magnetic and magnetocaloric properties of the A2LnSbO6 lanthanide oxides on the frustrated fcc lattice' in Inorganic chemistry (10.1021/acs.inorgchem.3c01137). Includes structural and magnetic characterisation as detailed in the main text and SI. For more details on the files please refer to the readme files within each figure folder. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2023 |
| Provided To Others? | Yes |
| URL | https://www.repository.cam.ac.uk/handle/1810/361413 |