EPR studies of some f/sup n/ and d/sup n/ electronic impurities in KTaO/sub 3/ single crystals

Single crystals of the cubic perovskite host, potassium tantalate (KTaO/sub 3/), doped with iron group, lanthanide, and actinide impurities have been investigated using the technique of electron paramagnetic resonance (EPR). The EPR spectra of Yb/sup 3 +/ and U/sup 5 +/ have been observed for the first time in potassium tantalate by employing crystals co-doped with both impurities. Multiple doping of the material during the crystal growth process avoided the production of semiconducting KTaO/sub 3/ and resulted in the incorporation of adequate concentrations of the trivalents lanthanide ion Yb/sup 3 +/. The EPR results indicate that Yb/sup 3 +/ occupies a site in which the local symmetry is axial as a result of nearby charge compensation. Pentavalent uranium is found to occupy a substitutional cubic symmetry site. EPR investigations of Cu/sup 2 +/, Co/sup 2 +/, Mn/sup 2 +/, Ni/sup 3 +/, and Fe/sup 3 +/ were also carried out.