Imperial College London
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PROFESSOR A DAVID CAPLIN

Faculty of Natural Sciences, Department of Physics

Distinguished Research Fellow
 
 
 
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Contact

 

+44 (0)20 7594 7608d.caplin

 
 
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Assistant

 

Mrs Carolyn Dale +44 (0)20 7594 7579

 
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Location

 

804Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Lovell:2015:10.1002/aenm.201401639,
author = {Lovell, E and Pereira, AM and Caplin, AD and Lyubina, J and Cohen, LF},
doi = {10.1002/aenm.201401639},
journal = {Advanced Energy Materials},
title = {Dynamics of the first-order metamagnetic transition in magnetocaloric La(Fe,Si)(13): Reducing hysteresis},
url = {http://dx.doi.org/10.1002/aenm.201401639},
volume = {5},
year = {2015}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The influence of dynamics and sample shape on the magnetic hysteresis in firstorder magnetocaloric metamagnetic LaFe13–xSix with x = 1.4 is studied. In solidstate magnetic cooling, reducing magnetic and thermal hysteresis is critical for refrigeration cycle efficiency. From magnetization measurements, it is found that the fast fieldrate dependence of the hysteresis can be attributed to extrinsic heating directly related to the thickness of the sample and the thermal contact with the bath. If the field is paused partway through the transition, the subsequent relaxation is strongly dependent on shape due to both demagnetizing fields and thermal equilibration; magnetic coupling between adjacent sample fragments can also be significant. Judicious shaping of the sample can both increase the onset field of the ferromagnetic–paramagnetic (FM–PM) transition but have little effect on the PM–FM onset, suggesting a route to engineer the hysteresis width by appropriate design. In the fieldpaused state, the relaxation from one phase to the other slows with increasing temperature, implying that the process is neither thermally activated or athermal; comparison with the temperature dependence of the latent heat strongly suggests that the dynamics reflect the intrinsic free energy difference between the two phases.
AU  - Lovell,E
AU  - Pereira,AM
AU  - Caplin,AD
AU  - Lyubina,J
AU  - Cohen,LF
DO  - 10.1002/aenm.201401639
PY  - 2015///
SN  - 1614-6840
TI  - Dynamics of the first-order metamagnetic transition in magnetocaloric La(Fe,Si)(13): Reducing hysteresis
T2  - Advanced Energy Materials
UR  - http://dx.doi.org/10.1002/aenm.201401639
UR  - https://onlinelibrary.wiley.com/doi/abs/10.1002/aenm.201401639
UR  - http://hdl.handle.net/10044/1/22042
VL  - 5
ER  -
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