期刊
ADVANCED ENERGY MATERIALS
卷 5, 期 6, 页码 -出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/aenm.201401639
关键词
hysteresis; magnetic refrigeration; magnetic relaxation; magnetocaloric effects; metamagnetism
类别
资金
- European Community [310748]
- EPSRC
- EPSRC [EP/E016243/1] Funding Source: UKRI
- Engineering and Physical Sciences Research Council [1226655, EP/E016243/1] Funding Source: researchfish
The influence of dynamics and sample shape on the magnetic hysteresis in first-order magnetocaloric metamagnetic LaFe13-xSix with x = 1.4 is studied. In solid-state magnetic cooling, reducing magnetic and thermal hysteresis is critical for refrigeration cycle efficiency. From magnetization measurements, it is found that the fast field-rate 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 field-paused 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.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据