Broadband EPR Spectroscopy of Tb.sup.3+ and Fe.sup.2+ Ions in YAlO.sub.3 Single Crystals

A YAlO.sub.3 crystal with an admixture of iron was studied by broadband EPR spectroscopy. Two types of paramagnetic centers were found. The energy level scheme of one of them is a singlet and a doublet with a splitting of 215.2 GHz. This center is presumably associated with the Fe.sup.2+ ion. The second center was identified as the Tb.sup.3+ ion, which entered the crystal as an uncontrolled impurity. The localization of the impurity ion in the YAlO.sub.3 crystal lattice is determined for each case. Within the framework of the existing theory, calculations are carried out and spectral parameters are determined.