Extraordinary Hall effect in magnetic granular alloys
Extraordinary Hall effect in magnetic granular alloys
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DOI：
10.1016/s0304-8853(96)00494-5
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发表时间：
1997-02-01
影响因子：
2.7
通讯作者：
Chshiev, M
中科院分区：
文献类型：
--
作者：
Granovsky, A;Brouers, F;Chshiev, M
本文对具有巨磁电阻效应的磁性颗粒合金中的异常霍尔效应进行了理论研究。在考虑自旋-轨道相互作用引起的斜散射的Zhang-Levy模型中，考虑了自旋极化电子在磁性颗粒、非磁性基体以及颗粒与基体界面处的杂质散射. EHE系数R（s）的计算使用Boltzmann方程进行。我们表明，颗粒系统的R（s）可能大于均匀铁磁体。此外，这些系数可以具有相反的符号。该理论预测，当基体中的电子平均自由程远大于颗粒内时，EHE电阻率与颗粒的浓度成正比。我们没有发现R（s）和ρ（2）之间的任何相关性，其中ρ是粒状合金的电阻率。然而，对于某些参数值，EHE电阻率与ρ（3.9）成正比。这与Co20 Ag 80的实验数据一致。
We present the results of a theoretical investigation of the extraordinary Hall effect (EHE) in magnetic granular alloys which exhibit giant magnetoresistance. We consider the impurity scattering of spin-polarized electrons within the magnetic granules, the non-magnetic matrix and at the interfaces between the granules and the matrix in the Zhang-Levy model taking into account the skew scattering due to the spin-orbit interaction. The calculation of the EHE coefficient R(s) was carried out using the Boltzmann equation. We show that R(s) for granular systems may be larger than that for an homogeneous ferromagnet. Moreover, these coefficients may have opposite sign. The theory predicts that the EHE resistivity is proportional to the concentration of the granules when the electron mean-free path in the matrix is much larger than within the granules. We do not find any correlation between R(s) and rho(2), where rho is the resistivity of the granular alloy. However, for some values of the parameters, the EHE resistivity is proportional to rho(3.9). This is in agreement with the experimental data for Co20Ag80.