Structure and magnetoresistance of a Ni79.7Fe14.0Co2.8Zr2.0Cu1.5 thin film

The structure and magnetoresistance R of thin films based on Ni₈₀Fe₂₀ permalloy doped with Co, Zr, and Cu have been examined by X-ray diffraction analysis and resistance measurement. The films have been obtained by ion plasma sputtering on oxidized silicon, fused quartz, and glass ceramic cold substrates. It has been shown that the structure of a film in the initial state is a mixture of solid solutions based on two phases: Ni(fcc) particles with a size of L ≈ 8 nm and (Zr_0.67Ni_0.22O_0.11)γ particles with a size of L ≈ 12 nm. The R(H) dependences on the strength and direction of the magnetic field H have been obtained at room temperature for film samples in the initial state and after isothermal annealing at 653 K for 1 h. According to R(H) dependences and X-ray diffraction analysis, films in the initial state are assumingly in a superparamagnetic state, whereas they exhibit ferromagnetic properties after isothermal annealing.