Resonator with magnetic-field concentrator for study of specimens under axial compression

This paper proposes a resonator design that allows small specimens under uniform axial compression to be studied over a wide temperature range and increases the sensitivity of the spectrometer. The resonator is for the 8-mm band with a magnetic-field concentrator. The concentrator increases the sensitivity of the microwave spectrometer and allows the study of the small specimens for electron paramagnetic resonance studies at helium and nitrogen temperatures