Controlling Acoustic Metamaterials with Magnetic Resonances: The Best of Both Worlds
Lead Research Organisation:
University of Sheffield
Department Name: Materials Science and Engineering
Abstract
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Publications
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Adhikari A
(2021)
Surface acoustic wave assisted depinning of magnetic domain walls
in Journal of Physics: Condensed Matter
Description | The work on the main workplan of the grant was affected by the COVID19 pandemic. However, we have developed new laboratory infrastructure for preliminary characterisation of magnetoacoustic devices, and have fabricated several sets of devices for study by our collaborators at the University of Exeter. We are now able to successfully fabricate magnetoacoustic devices, and have shown that these exhibit acoustically induced ferromagnetic resonance. We have explored this in a number of different material systems to determine which produce the strongest coupling. We are now moving forward with novel devices designs that we expect will exhibit enhanced non-reciprocity of spin-wave absorption. In particular we have developed thin film superlattices that sit at the interface between having in-plane and out-of-plane anisotropy. We expect these to exhibit much stronger coupling to SAWs than standard thin films. We have also begun a new collaboration with researchers at the University of Nebraska-Lincoln where we have used mathematical modelling to study how SAWs would affect the depinning of magnetic domain walls in new memory devices. Our modelling has led to the proposal of a new mechanism (based on the modulation of energy barriers against depinning) that can explain our collaborators experimental results. Further modelling of how SAWs affect depinning from artificial defect sites has also been completed, and has demonstrated that SAWs will produce similar modulations of energy barriers as in the above study. We are now attempting to apply these models to experimental data. |
Exploitation Route | It is a little to early to say at this stage, but in the short term our findings are likely to be of greatest interest to other academic researchers. |
Sectors | Other |
Description | Collaboration with Universities of Durham and Poznan |
Organisation | Durham University |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | We performed ferromagnetic resonance measurements on CoFe/Pt thin films with transition metal delta layers in order to determine their gilbert damping constants. |
Collaborator Contribution | Samples were prepared at Poznan University, with initial characterisation taking place at the University of Durham. |
Impact | None so far |
Start Year | 2023 |
Description | Collaboration with Universities of Durham and Poznan |
Organisation | Poznan University of Technology |
Country | Poland |
Sector | Academic/University |
PI Contribution | We performed ferromagnetic resonance measurements on CoFe/Pt thin films with transition metal delta layers in order to determine their gilbert damping constants. |
Collaborator Contribution | Samples were prepared at Poznan University, with initial characterisation taking place at the University of Durham. |
Impact | None so far |
Start Year | 2023 |
Description | Collaboration with University of Nebraska-Lincoln (Prof. Shireen Adenwalla) |
Organisation | University of Nebraska-Lincoln |
Department | Department of Physics and Astronomy |
Country | United States |
Sector | Academic/University |
PI Contribution | My group have produced models and performed calculations of the effects of surface acoustic waves on the thermal activated depinning of domain walls in materials with out-of-plane anisotropy. Our work has shown that for low frequency/long wavelength SAWs the mechanism for SAW assisted depinning is likely through modulation of the DW pinning potential. |
Collaborator Contribution | Our partners at UNL have provided high quality experimental data for us to fit our models to. |
Impact | A paper is in preparation for submission to Physical Review Applied. |
Start Year | 2020 |