Imperial College London
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Professor Lesley F Cohen

Faculty of Natural Sciences, Department of Physics

Associate Provost (Equality, Diversity and Inclusion)
 
 
 
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Contact

 

+44 (0)20 7594 7598l.cohen Website CV

 
 
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Assistant

 

Mrs Carolyn Dale +44 (0)20 7594 7579

 
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Location

 

1111Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Morrison:2009:10.1103/PhysRevB.79.134408,
author = {Morrison, K and Moore, JD and Sandeman, KG and Caplin, AD and Cohen, LF},
doi = {10.1103/PhysRevB.79.134408},
journal = {PHYS REV B},
title = {Capturing first- and second-order behavior in magnetocaloric CoMnSi0.92Ge0.08},
url = {http://dx.doi.org/10.1103/PhysRevB.79.134408},
volume = {79},
year = {2009}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Here we examine the constituent components that make a magnetocaloric material attractive for application. The field-temperature phase diagram is studied and using calorimetry, the first-order and second-order components of the magnetic field-driven magneto-structural phase transition in CoMnSi0.92Ge0.08 are extracted. It is demonstrated that below 262 K the transition shows a latent heat component associated with first-order behavior when the material changes from antiferromagnetic to ferromagnetic order. Such a transition is known as a metamagnetic transition. We identify 262 K as a tricritical point and above this temperature T-crit the transition shows only continuous, second-order characteristics. Hall-probe imaging that has a five micron pixel resolution is then used to study the striking differences in the spatial evolution of the transition above and below T-crit. We demonstrate that the hysteresis of the transition is linearly related to the magnitude of the latent heat; an observation that has important implications for the use of this and other first-order systems for application as magnetic refrigerants.
AU  - Morrison,K
AU  - Moore,JD
AU  - Sandeman,KG
AU  - Caplin,AD
AU  - Cohen,LF
DO  - 10.1103/PhysRevB.79.134408
PY  - 2009///
SN  - 1098-0121
TI  - Capturing first- and second-order behavior in magnetocaloric CoMnSi0.92Ge0.08
T2  - PHYS REV B
UR  - http://dx.doi.org/10.1103/PhysRevB.79.134408
UR  - http://hdl.handle.net/10044/1/18893
VL  - 79
ER  -
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