Influence of the effective layer thickness with Dy and Temperature of heat treatment on the structural-phase state and magnetoresistive properties of Ni/Dy/Co three-layer films

摘要

The influence of the effective Dy layer thickness and temperature of the heat treatment on the structural-phase state, electrophysical and magnetoresistive properties of three-layer Ni/Dy/Co films have been analyzed. The research result of the phase composition investigation in the as-deposited state corresponds to fcc-Ni + hcp-Co + fcc-Co + qa-Dy. It was determined that the system is characterized by a relatively large value of the temperature coefficient of resistance (~10^-3K^-1) and has resistivity of the order of ρ~ 10^-6 Om m, that is due to the presence of a large number of defects in the crystalline system structure. The investigation in the as-deposited state indicates an anisotropic behavior of the magnetoresistance dependence, the magnitude of which varies with the change in the effective thickness of the Dy layer. The heat treatment within the limits of 500-800 K does not lead to a change in the phase composition and the nature of the dependence of magnetoresistance (B), but only causes recrystallization processes and changes in the value of the magnetoresistance amplitude. The sharp change in the magnetoresistance and the coercive force with the change of the orientation of the sample in the external magnetic field allows to consider these films as a sensitive element of the AMR-sensor.