Radiation and thermally induced effects in YAlO3:Mn crystals

We have studied effects induced by γ-radiation and temperature in Mn-doped YAlO3 crystals. The studies have been performed by means of optical spectroscopy that include measuring of optical absorption changes induced by γ-radiation and elevated temperature as well as thermally stimulated luminescence (TSL). It has been shown that under γ-irradiation of YAlO3:Mn crystals, along with the ionization of MnAl4+ ions (MnAl4+→MnAl5++e−), some additional coloration processes take place. This additional coloration is characterized by a wide intense band centered at 26,000–25,000 cm−1 that is ascribed to color centers intrinsic to YAlO3 lattice. This coloration is removed by the way of crystal warming at T⩾350 K, while the coloration caused by MnAl5+ ions is removed at higher temperature (T⩾500 K). The observed TSL glow of irradiated crystals reveals three peaks near 360, 400 and 500 K that correspond to three types of traps. Parameters of the traps have been determined. The TSL emission corresponds to intra-center luminescence of MnAl4+ and MnY2+ ions. The possible ionization and trapping mechanisms in YAlO3:Mn crystals are discussed.