Angle and thickness dependence of magnetoresistance peaks in thin nickel films

In this paper, we report a dependence of the magnetoresistance in thin nickel films on the angle θ between the magnetic field and the film surface. We find a strong variation of the magnetic field difference between two MR peaks (FDMP). In thinner films less than 400 Å thick, the FDMP is well explained by a 1/cos θ function, which can be obtained using the concept of an effective magnetization field. However, in thicker films, the FDMPʹs rate of increase is found to become faster than 1/cos θ. This different behavior is considered to be related to both the grain formation and the grain size in the films. Consequently, due to the different grain configuration, randomization of the magnetization vectors during the reversed magnetic field process in thicker films might be achieved through a three-dimensional process while in thinner films this is achieved through a two-dimensional process.