magnetic resonance (EDMR) spectrometer to perform sensitive EDMR measurements of 4H-
silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors at sub-millitesla
(mT) magnetic fields. The new spectrometer design enables the detection of so-called ultra-
strong coupling effects such as multiple-photon transitions and Bloch–Siegert shifts. In this
paper, we present a new spectrometer design and discuss ultra-low field FS-EDMR …