Annealing Effects on the Magnetic Properties of SiO/IrMn/Co(10)/Cu(X)/Co(2)/Py(8)/Pt Multilayered Films

Abstract

In this work, the magnetic properties of Co(10 nm)/Cu(X nm)/Co(2 nm)/Py(8 nm)/Pt magnetic-nonmagnetic multilayered thin film grown on an antiferromagnetic IrMn buffer layer have been studied. The multilayered thin films were deposited on pre-cleaned SiO2 substrate by using a magnetron sputtering technique in ultra-high vacuum conditions. To investigate the effects of the buffer layer on magnetic properties, we prepared two sets of samples, one of which just on as-prepared IrMn and the other on IrMn buffer layer that was annealed at about 500 K in ultra-high vacuum conditions. In order to modulate the exchange coupling between two ferromagnetic thin layers, we put a nonmagnetic copper spacer layer with varying thicknesses. We applied conventional dc magnetization, magneto-resistivity (MR), and ferromagnetic resonance (FMR) techniques to investigate dc and high-frequency magnetic properties. The magnetic parameters, such as magnetization, magnetic anisotropies, exchange anisotropy, and the spacer thickness dependence of the exchange interactions over the nonmagnetic layer, were analyzed. We have seen that the magnetic properties are strongly affected not only by isolated single magnetic layer properties, but also by the features of the buffer and spacer layers. The magneto-resistivity changes character from anisotropic magneto-resistivity to the giant magneto-resistivity in the case of the annealed buffer layer, and they are spacer thickness-dependent as well.