The FMR magnetic reproducing head using a microwave guide

A flux sensitive magnetic reproducing head using permeability change of magnetic thin films by the magnetic flux from the media is described. The head consists of a short-circuited coplanar type guide and a flux sensor of magnetic thin films located at the end of the waveguide. It is shown that the permeability change is enlarged by using ferromagnetic resonance, and it can be detected by rectifying the voltage amplitude of the standing wave in the waveguide. In the reproducing measurement from a magnetic tape, in which the relative speed between the head and the tape is 5 m/s, a signal of 1 mV and C /N=50 dB are obtained at 1 MHz with microwave power of 15 dBm