Luminescence Spectra of Sm³⁺ in BaTiO₃ Host Lattice

Abstract

Luminescence spectra of Sm 3+ at a Ti 4+ site in BaTiO 3 host lattice were investigated in a wide range of temperatures including those above the Curie point. Any shifts of emission lines were not observed between -196°C and 145°C. The ferro-to-paraelectric transition is considered not to influence the strength of the electrostatic field surrounding Sm 3+ so much as to induce a detectable shift of the 4 f electron levels. Some singlet lines were found to split into doublets associated with the transitions of the crystal structure from the cubic to tetragonal and also from the rhombohedral to orthorhombic phase. These facts are accounted for by considering the change of the site symmetry around Sm 3+ .