Anomalous anisotropic magnetoresistance in epitaxial Fe 3 O 4 thin films on MgO(001)
Anomalous anisotropic magnetoresistance in epitaxial Fe 3 O 4 thin films on MgO(001)
复制标题
DOI：
10.1103/physrevb.78.214402
复制
发表时间：
2008-12
影响因子：
3.7
通讯作者：
R. Ramos;S. Arora;I. Shvets
中科院分区：
文献类型：
--
作者：
R. Ramos;S. Arora;I. Shvets
本文报道了在MgO（001）上生长的磁铁矿$({\text{Fe}}_{3}{\text{O}}_{4})$外延膜和磁铁矿单晶的各向异性磁电阻（AMR）的角依赖性。在200 K以上的温度下，AMR具有双重对称性。当样品冷却到200k以下时，会出现一组额外的峰。这些在较低的温度下占主导地位，显示出整体的四重对称。对AMR中附加各向异性的观察表明，在比Verwey转变温度高得多的温度下，电荷有序的形成可能与磁铁矿中极化子的形成有关。
Studies of the angular dependence of the anisotropic magnetoresistance (AMR) are reported for epitaxial films of magnetite $({\text{Fe}}_{3}{\text{O}}_{4})$ grown on MgO(001) and also for single crystals of magnetite. The characteristic feature of the AMR is a twofold symmetry at temperatures above 200 K. As the samples are cooled below 200 K, an additional set of peaks appears. These become dominant at lower temperatures showing an overall fourfold symmetry. Observation of additional anisotropy in the AMR points to formation of charge ordering at much greater temperatures than the Verwey transition temperature and is possibly related to the polaron formation in magnetite.