Magnetic anisotropy in epitaxial CrO2 and CrO2/Cr2O3 bilayer thin films
Magnetic anisotropy in epitaxial CrO2 and CrO2/Cr2O3 bilayer thin films
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DOI：
10.1103/physrevb.74.024420
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发表时间：
2006-07-01
影响因子：
3.7
通讯作者：
Gupta, A.
中科院分区：
文献类型：
--
作者：
Frey, N. A.;Srinath, S.;Gupta, A.
利用共振射频横向磁化率（TS）研究了CVD外延CrO 2薄膜和Cr2 O3/CrO 2双层膜的有效磁各向异性。CrO 2是一种高自旋极化的铁磁体，而Cr2 O3在室温以上表现出磁电效应和反铁磁性。在CrO 2中，测量值的室温各向异性常数缩放的膜厚度和TS数据的影响，在低温下由于晶格失配与衬底引起的界面应变的磁弹性贡献。在CrO_2/Cr_2O_3双层膜中，M-H环显示了增强的磁化率，而没有明显的环移，横向磁化率显示了与铁磁和反铁磁相相关的特征。此外，一个相当大的各向异性领域和大的K-eff值的扩大，观察取决于分数的Cr2 O3存在。这种异常的行为，观察到的第一次，不能占的CrO 2单独的可变厚度，是可能的交换耦合CrO 2和Cr2 O3阶段，显着影响有效的磁各向异性之间的指示。(c)2006年，美国物理学会。
We have investigated the effective magnetic anisotropy in CVD-grown epitaxial CrO2 thin films and Cr2O3/CrO2 bilayers using resonant radio-frequency transverse susceptibility (TS). While CrO2 is a highly spin polarized ferromagnet, Cr2O3 is known to exhibit magnetoelectric effect and orders antiferromagnetically just above room temperature. In CrO2, the measured values for the room temperature anisotropy constant scaled with the film thickness and the TS data is influenced by magnetoelastic contributions at low temperature due to interfacial strain caused by lattice mismatch with the substrate. In CrO2/Cr2O3 bilayers M-H loops indicated an enhanced coercivity without appreciable loop shift and the transverse susceptibility revealed features associated with both the ferromagnetic and antiferromagnetic phases. In addition, a considerable broadening of the anisotropy fields and large K-eff values were observed depending on the fraction of Cr2O3 present. This anomalous behavior, observed for the first time, cannot be accounted for by the variable thickness of CrO2 alone and is indicative of possible exchange coupling between CrO2 and Cr2O3 phases that significantly affects the effective magnetic anisotropy. (c) 2006 American Institute of Physics.