Application of radio spectroscopy methods for the study of thermoelectrics with a chalcopyrite structure

Doped chalcopyrite compounds are considered. The results of studying the spectral parameters by the $^{63,65}$Cu NMR method in a local field, as well as by the EPR method in the temperature range 15–300 K are presented. The observed broadening of the resonance lines of the NMR spectra and the detection of a paramagnetic signal in the sample at a temperature of 15 K indicate the appearance of anti-structural defects. The rapid change in the shape of the EPR spectrum line, in the temperature range 100–130 K, is associated with the structural-phase transition.