Search

The effective spin mixing conductance Gmixeff in WxMo1−x (WMo)/Y3Fe5O12 (YIG) heterostructure has been studied by the measurements of electron spin resonance and spin pumping technique which are based on the ferromagnetic resonance (FMR). It is interesting to find that the FMR linewidth for both YIG single layer and WMo/YIG heterostructures shows twofold and fourfold symmetry contributions although Gmixeff exhibits isotropic feature. The Gmixeff and resistivity ρ present a maximum and minimum value at x = 0.42 for WxMo1−x/YIG heterostructures, respectively, which could be ascribed to the complex phase constituents of the alloy films. This work emphasized that the consistent measurement orientation of YIG single layer and WMo/YIG heterostructures should be strictly obeyed to get the accurate Gmixeff owing to the anisotropic feature of in-plane FMR linewidth, which has always been ignored. Proper alloyed Mo could adjust the spin current related phenomenon of W based alloys, to achieve the high efficiency of spin current production from the large effective spin mixing conductance.

The magnetoresistance of a MgO-based magnetic tunnel junction (MTJ) was studied experimentally. The magnetoresistance as a function of current was measured systematically on MTJs for various MgO cross sectional areas and at various temperatures from 7.5 to 290.1 K. The resistance current dependence of the MTJ was also measured for different angles between the two ferromagnetic layers. By considering particle and angular momentum conservation of transport electrons, the current dependence of magnetoresistance can be explained by the changing of spin polarization in the free magnetic layer of the MTJ. The changing of spin polarization is related to the magnetoresistance, its angular dependence and the threshold current where TMR ratio equals zero. A phenomenological model is used which avoid the complicated barrier details and also describes the data.