Understanding The Real Scaling in Anomalous Hall Effect

Understanding The Real Scaling in Anomalous Hall Effect 田源, 金晓峰 通过对外延生长Fe薄膜反常霍尔效应的研究，我们提出了反常霍尔效应与纵向电阻率正确 的函数依赖关系。这里通过实验数据展示了新的函数关系的正确性，建立模型理解这种依 赖关系，并且讨论了超出当前理解，可能需要新的理论模型来描述的现象。 Measure the Anomalous Hall Effect (AHE): Scaling We Established (Previous Work) Described by resistivity: Mg. O 4 nm Fe MBE growth B Zero temperature resistivity (Caused by impurity and surface) Ga. As (100) It can fits into different experimental data AHE resistivity Intrinsic contribution to AHE, constant at low Temperature in Fe Direct Evidence of Its Superiority in Our Fe Data Hall bar: 1. 5 mm Linear form of old formula 6 mm as y is found to be a function of longitudinal resistivity : Experimental Diversification in the Scaling of in Finite Temperature Fe Ni A. Fert and O. Jaoul, B. PRL. (1972) R. W. Klaffy, Phy. Rev. (1967). as x as y Not a line A line Co J. Kotzler and W. Gil, PRB (2005) The Temperature Independent Part Is Not Trivial! In conductivity language, it’s not temperature-independent at all! as x Linear form of our formula Beyond Our Scaling, There are Phenomena Need More Than Known Mechanisms Hint from resistivity to conductivity: Our Picture Our scaling We explain the first term by skew scattering. (The second term can be understand in a similar way by side-jump, not shown here) Schematic plot of skew scattering The deviation from our scaling is not a temperature independent resistivity any more. It is possible that the scattering center is smeared out by phonons at certain temperature Conclusions ØNew scaling relationship for in AHE has been proposed. ØA model to understand terms in the scaling is presented. ØWe also found small extra effect in Fe beyond the scaling, which need new theory to explain.