Influence of boron doping on magnetic properties and microwave characteristics of MnIr/FeCoB multilayers

Abstract

A detailed investigation of the influence of B doping on the magnetic properties and high frequency characteristics of FeCoB/MnIr multilayered thin films was carried out. Exchange bias was found to decrease monotonically with B doping possibly due to less favorable of AF phase of MnIr in the samples with rich B concentration. However, with small amount of doping up to 9 of B concentration, the MnIr fcc (111) peaks become more prominent and the real part of permeability enhanced. Our results suggest no correlation between the structural phase of MnIr and the exchange bias. Also, the influences of B doping on several static and dynamic parameters, such as rotational magnetic anisotropy field, coercivity, saturation magnetization, resonance frequency, and effective damping factor are presented and discussed. Our results support the claim that the coercivity enhancement and the arising of rotational anisotropy may have the same physical origin. © 2012 American Institute of Physics.