Magnetoresistance in 82Ni-Fe/Al-Al2O3/Co Junction-Dependence of the Tunneling Conductance on the Angle between the Magnetizations of Two Ferromagnetic Layers

The magnetoresistance of a ferromagnetic tunneling junction in 82Ni-Fe/ Al-Al2O3/Co, prepared by electron beam evaporation in a 1×10^-6 Torr vacuum, was studied. Tunneling was confirmed to occur by measuring the I-V characteristic and its temperature dependence, which were in good agreement with Stratton´s tunneling theory. The hysteresis curve of the magnetoresistance corresponds well to that of the magnetization. The magnetoresistance ratio δR/R was 2.7% and 3.5% at room temperature and 77K respectively. The dependence of the tunneling conductance (G) on the angle (θ) between the magnetizations of the two ferromagnetic layers was also measured. The G values can be expressed as G=G0(l+ϵcosθ) (where G0 and ϵ are constants), which agrees well with the theory proposed by Slonczewski.