Magnetic polarization selective spectroscopy of magnetic thin films probed by wideband crossed microstrip circuit in GHz regime

We have developed a method to obtain wideband magnetic polarization selective spectra of magnetic thin films by using circularly polarized microwaves. The combination of an over-coupled crossed microstrip resonator and a hybrid coupler enables broadband and accurate control of circularly polarized microwaves. The performance of the present method was demonstrated with an yttrium iron garnet thin film, and we detected the magnetic polarization dependence of a Kittel mode and a perpendicular standing spin wave mode in the range of 3-20 GHz. In addition, three types of crossed microstrip resonators were systematically studied with experiments and simulations. As a result, we achieved the polarization efficiency of 80% and found how to optimize the crossed microstrip resonator depending on the desired sensitivity, bandwidth, or sample size.

Automated summary

The paper presents a method for obtaining wideband magnetic polarization selective spectra of magnetic thin films using circularly polarized microwaves. The method combines an over-coupled crossed microstrip resonator and a hybrid coupler for accurate control of circularly polarized microwaves. The performance of the method is demonstrated with an yttrium iron garnet thin film, and the polarization dependence of Kittel mode and perpendicular standing spin wave mode is detected in the range of 3-20 GHz.