Wideband epr spectroscopy of Tb$^{3+}$ and Fe$^{2+}$ ions in YAlO$_{3}$ single crystals

An iron-doped YAlO$_{3}$ crystal was studied by wideband EPR spectroscopy. Two types of paramagnetic centers have been found. The energy scheme of the levels of one of them is a singlet and a doublet with a splitting between them of 215.2 GHz. This center is presumably due to the Fe$^{2+}$ ion. The second center was identified as a Tb$^{3+}$ ion that entered the crystal as a trace impurity. For each case, the localization of the impurity ion in the YAlO$_{3}$ crystal lattice is determined. Within the framework of the existing theory, calculations were made and spectral parameters were determined.