Scattering mechanisms in textured FeGe thin films: Magnetoresistance and the anomalous Hall effect
Scattering mechanisms in textured FeGe thin films: Magnetoresistance and the anomalous Hall effect
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DOI：
10.1103/physrevb.90.024403
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发表时间：
2014-07-09
影响因子：
3.7
通讯作者：
Marrows, C. H.
中科院分区：
文献类型：
--
作者：
Porter, N. A.;Gartside, J. C.;Marrows, C. H.
采用磁控溅射法制备了FeGe织构薄膜，其有序温度为T-N = 276 +/- 2 K。从5k到室温，各种散射过程对整体纵向电阻率和霍尔电阻率有影响。这些是通过结合磁强计和磁输运测量来研究的。高场磁阻（MR）显示三种清晰的温度状态：在低温下，洛伦兹力MR占主导地位，在T近似于80k以上，自旋波散射占主导地位，而最后，当T大于或类似于200k时，来自波动局部矩的散射描述了MR。在低场，磁化强度不再是技术上饱和的地方，我们发现磁电阻与磁化强度的平方成比例。表明由锥形相自旋解绕引起的磁共振与磁畴壁的机制相似。这种MR只能在大约200k的温度下可见。在纵向电阻率的温度或场依赖性中，没有发现任何特征表明在T-N处存在潜在的磁相变：在更低的温度下，行为的显著变化。反常霍尔效应具有显著的温度依赖性，其中反常霍尔电阻率与纵向电阻率成二次标度；与反常霍尔标度理论的比较表明，我们的系统处于固有的“中等脏”状态。最后，我们发现了拓扑霍尔效应的证据，其大小类似于100 μ Omega cm。
A textured thin film of FeGe was grown by magnetron sputtering with a helimagnetic ordering temperature of T-N = 276 +/- 2 K. From 5 K to room temperature, a variety of scattering processes contribute toward the overall longitudinal and Hall resistivities. These were studied by combining magnetometry and magnetotransport measurements. The high-field magnetoresistance (MR) displays three clear temperature regimes: Lorentz force MR dominates at low temperatures, above T approximate to 80 K scattering from spin-waves predominates, while finally for T greater than or similar to 200 K scattering from fluctuating local moments describes the MR. At low fields, where the magnetization is no longer technically saturated, we find a scaling of magnetoresistance with the square of the magnetization, indicating that the MR due to the unwinding of spins in the conical phase arises from a similar mechanism to that in magnetic domain walls. This MR is only visible up to a temperature of about 200 K. No features can be found in the temperature or field dependence of the longitudinal resistivity that belie the presence of the underlying magnetic phase transition at T-N: the marked changes in behavior are at much lower temperatures. The anomalous Hall effect has a dramatic temperature dependence in which the anomalous Hall resistivity scales quadratically with the longitudinal resistivity: comparison with anomalous Hall scaling theory shows that our system is in the intrinsic "moderately dirty" regime. Lastly, we find evidence of a topological Hall effect of size similar to 100 mu Omega cm.