Anisotropic Magnetic Resistance And Spin Rectification Effect In Metal Magnetic Films

Spin rectification effect, which transforms dynamical spin precession into direct electrical signal, has been a research hotspot due to its advantages in detecting of spin dynamics and microwaves. Theoretically, stronger spin rectification effect can be achieved by increasing the anisotropic magnetic resistance (AMR) of magnetic materials, which makes the application of spin rectification effect possible. This thesis concerns the AMR and spin rectification effect in metal magnetic films, the results are as follows:1. AMR in metal magnetic micro-stripe films.FeNi films were deposited by magnetron sputtering, and then were etched into10micrometers wide stripes using electron beam lithography by a lift-off process, finally the stripes were annealed at different temperatures. The magnitude of AMR in these stripes only reached the order of a few thousandths due to non-magnetic scattering. In order to reduce non-magnetic scattering effect, another series of stripe samples were prepared with higher deposition speed. The AMR up to3.2%was obtained in post-processed samples, which approached the value3.8%of bulk materials. Microstructures measurements showed that grain size in FeNi films played a crucial role in determining the value of AMR.2. Spin rectification effect in metal magnetic micro-stripe films. Micro-stripes and spin dynamos were prepared using lift-off process. Due to the enhancement of AMR effect, the rectification signal of spin dynamos was increased by two orders of magnitude, which enables the observation of rectification signal in Micro-stripes without the use of co-planar waveguides. By linearly fitting of the rectification signals in these two kinds of devices, ferromagnetic resonance and dispersive relations were analyzed. The magnetic parameters of the devices and polarization of microwave magnetic field were also obtained. Spin dynamics were studied by using spin rectification effect.