Electron spin resonance of magnetic materials in high fields and high frequencies

Observation and analysis of electron spin resonance of many kinds of magnetic materials have been performed with high frequencies provided by Gunn oscillators, backward traveling wave tubes and far-infrared lasers and also with a vector network analyzer in both pulsed high magnetic fields up to 40 T and steady field up to 20 T. The magnetic behavior of quantum spin systems and metallic materials has been investigated.