Magnetoresistive Effect of Vacuum Evaporated Ni-Co Films

Because of the large anisotropic magnetic field of Ni-Co films, there have been few reports on their magnetoresistive effect. The authors succeeded in vacuum evaporation of Ni-Co (Ni content 60 - 85 percent) films with a small anisotropic magnetic field, and studied the resulting magnetic properties. The magnetoresistive effect was largest for 77 percent Ni-Co, at approximately 5 percent, but when the substrate temperature was varied no change in the magnetoresistive effect was seen for temperatures above 250°C. A Ni-Fe film was placed next to Ni-Co film formed under optimum conditions, to obtain better low magnetic field sensitivity than is possible with Ni-Fe alone. Also, the Ni-Co had a nearly single domain structure, with stable magnetization.