On investigation of high T_c superconductors with Electron Paramagnetic Resonance spectrometers

Following the discovery of high T_c superconductors, many researchers have applied EPR spectrometers to investigate their properties using the regular instructions to operate the spectrometer. As no substantial information was obtained it was soon practically abandoned. Investigations performed recently with the EPR technique, using a different operating method than the conventional one and the introduction of a detailed theoretical study related to the interaction of the JV with the microwave magnetic field lead to new and important results related to properties of high anisotropy superconductors indicating that the EPR spectrometer can be used to investigate properties of high anisotropy superconductors. The failures when using conventional operating method to obtain meaningful results and the method used in the present work to carry out the measurements in a proper manner are presented. Some important results obtained in investigating high anisotropy superconductors by the EPR technique are presented.