Abstract
Sm-doped KBr single crystals were prepared by the Bridgman–Stockbarger technique. The samples show both radio-photoluminescence (RPL) and thermally-stimulated luminescence (TSL). The RPL is due to the valence change of the Sm ion (Sm3+ → Sm2+), induced by X-rays, so the photoluminescence emission by Sm2+ appears as a result of irradiation and the intensity increases with the irradiation dose. The emission of Sm2+ is due to the 5d–4f transitions. The RPL response seems to be related with the thermally-stimulated luminescence (TSL) on the same samples. The TSL emission is predominantly due to Sm2+, instead of Sm3+, indicating that capture of a hole by Sm2+ takes place. As a result of TSL (or heat treatment), Sm2+ reverts to Sm3+ as the original state. The thermal activation energies have been derived from TSL isothermal analyses, and the obtained values are 1.42, 1.55, 1.65, and 1.74 eV.
Published Version
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