Magnetostructural Coupling Drives Magnetocaloric Behavior: The Case of MnB versus FeB
Magnetostructural Coupling Drives Magnetocaloric Behavior: The Case of MnB versus FeB
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DOI：
10.1021/acs.chemmater.9b01476
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发表时间：
2019-06
影响因子：
8.6
通讯作者：
J. D. Bocarsly;E. Levin;Samuel A. Humphrey;T. Faske;W. Donner;Stephen D. Wilson;R. Seshadri
中科院分区：
文献类型：
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作者：
J. D. Bocarsly;E. Levin;Samuel A. Humphrey;T. Faske;W. Donner;Stephen D. Wilson;R. Seshadri
具有强耦合磁性和结构转变的材料可以表现出巨大的磁热效应，这在节能环保的冰箱、热泵和热磁发电机的设计中引起了人们的兴趣。然而，也存在一类没有已知的磁结构转变但显示出显著的磁热效应的材料。MnB最近被认为是这样一种化合物，在其居里温度（570 K）下显示出大的磁热效应，显示出利用热磁发电回收低级废热的前景。与此相反，我们发现，同构的FeB显示非常相似的磁有序特性，但不是一个有效的磁热。温度和磁场相关的衍射研究揭示了戏剧性的磁弹性耦合MnB，它存在没有磁结构转变。没有这样的行为是看到在FeB。此外，在MnB的磁性转变被证明是微妙的一阶，一个…
Materials with strongly coupled magnetic and structural transitions can display a giant magnetocaloric effect, which is of interest in the design of energy-efficient and environmentally friendly refrigerators, heat pumps, and thermomagnetic generators. There also exist, however, a class of materials with no known magnetostructural transition that nevertheless show remarkable magnetocaloric effects. MnB has been recently suggested as such a compound, displaying a large magnetocaloric effect at its Curie temperature (570 K) showing promise in recovering low-grade waste heat using thermomagnetic generation. In contrast, we show that isostructural FeB displays very similar magnetic ordering characteristics, but is not an effective magnetocaloric. Temperature- and field-dependent diffraction studies reveal dramatic magnetoelastic coupling in MnB, which exists without a magnetostructural transition. No such behavior is seen in FeB. Furthermore, the magnetic transition in MnB is shown to be subtly first-order, a...