The ferromagnetic resonance in WxMo1−x/YIG heterostructures

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.