EPR study of some rare-earth ions (Dy3+, Tb3+, and Nd3+) in YBa2CU3O6-compound

Abstract We investigate the low temperature X-band electron paramagnetic resonance (EPR) of YBa 2 Cu 3 O x compounds with x ≅6.0 doped with Dy 3+ , Tb 3+ , and Nd 3 . The EPR spectra of Dy 3+ and Tb 3+ have been identified. The EPR of Tb 3+ is used also to study the effect of suppression of high T c superconductivity by doping with Tb 3+ . The EPR of Nd 3+ is probably masked by the intense resonance of Cu 2+ . All experimental EPR results compare well with theoretical estimations.