Hall-effect characterization of the metamagnetic transition in FeRh
Hall-effect characterization of the metamagnetic transition in FeRh
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DOI：
10.1088/1367-2630/15/1/013008
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发表时间：
2013-01-08
影响因子：
3.3
通讯作者：
Marrows, C. H.
中科院分区：
文献类型：
--
作者：
de Vries, M. A.;Loving, M.;Marrows, C. H.
反铁磁基态和变磁过渡到铁磁态的CsCl有序FeRh外延层的特征在于使用霍尔和磁阻测量。在冷却到基态时，发现变磁转变与载流子密度的抑制相一致，该抑制的数量级低于铁磁状态所示的典型金属水平。在反铁磁状态的载流子密度是有限的Fe/Rh置换缺陷的本征掺杂，约两个电子每对原子交换，表明载流子密度的下降可能会更大，在更完美的标本。载流子密度惊人的大变化是变磁跃迁时费米面变化程度的明确定量指示，证实了跃迁时的熵释放是电子起源的，因此电子跃迁是变磁跃迁的基础。关于这种电子过渡的性质，有人建议，轨道选择性莫特过渡，选择性强相关的Fe 3d电子，可能会导致费米面的减少和变化的符号的磁交换从FM到AF冷却。
The antiferromagnetic ground state and the metamagnetic transition to the ferromagnetic state of CsCl-ordered FeRh epilayers have been characterized using Hall and magnetoresistance measurements. On cooling into the ground state, the metamagnetic transition is found to coincide with a suppression in carrier density of at least an order of magnitude below the typical metallic level that is shown by the ferromagnetic state. The carrier density in the antiferromagnetic state is limited by intrinsic doping from Fe/Rh substitution defects, with approximately two electrons per pair of atoms swapped, showing that the decrease in carrier density could be even larger in more perfect specimens. The surprisingly large change in carrier density is a clear quantitative indication of the extent of change at the Fermi surface at the metamagnetic transition, confirming that entropy release at the transition is of electronic origin, and hence that an electronic transition underlies the metamagnetic transition. Regarding the nature of this electronic transition, it is suggested that an orbital selective Mott transition, selective to strongly-correlated Fe 3d electrons, could cause the reduction in the Fermi surface and change in sign of the magnetic exchange from FM to AF on cooling.