High frequency measurements of spin valve recording heads

The high frequency response of a spin valve read head was characterized using noise spectroscopy and direct excitation from a co-planar waveguide. The magnetic noise spectrum which is proportional to the imaginary part of the device susceptibility, was measured using a low noise preamplifier and a spectrum analyzer. The response of the read head to electric and magnetic fields excitations was measured by connecting the CPW drive to port 1 of a 40 GHz network analyzer and the read head output to port2.