63,65Cu NMR and EPR Study of Doped Chalcopyrite Cu1-XPdXFeS2 Compounds

In the present paper, we applied 63,65Cu NMR in a local field and EPR methods to study a series of Cu1-XPdXFeS2 (x = 0–0.02) compounds. These compounds have the structure of widespread chalcopyrite and attract interest due to their thermoelectric properties. To improve its thermoelectric performance, most research efforts have been focused on the optimization of the properties of CuFeS2 by proper doping. A broadening of the resonance lines of 63,65Cu NMR and the change of EPR spectra may be the result of an increase in the number of defects in the crystal lattice of the compound such as antisite and vacancies, leading to a larger spread of EFG on the resonant copper nuclei. The results obtained show that changes in the periodicity of a crystal lead to a change in the environment of atoms and can significantly modify the physical properties of a substance.