Difference in the Nature of Eu3+ Environment in Eu3+-Doped BaTiO3 and BaSnO3

BaTiO3 and BaSnO3 samples doped with Eu3+ ions were prepared using glycine-nitrate gel combustion method. Relative intensities and line shapes of magnetic dipole allowed D-5(0) F-7(1) and electric dipole allowed D-5(0) F-7(2) transitions of Eu3+ from the hosts, BaTiO3 and BaSnO3, are significantly different. Based on detailed structural investigations, it is confirmed that synthesizedBaTiO(3) sample is tetragonal with no center of symmetry around Ba2+ ions. Unlike this BaSnO3 is cubic with centrosymmetric Ba2+ site. From X-ray diffraction and experimentally obtained Judd-Ofelt parameters ((2) and (4) values), it is confirmed that in BaTiO3 there is a decrease in the average Ba-O and Ba-Ba distances compared with that in BaSnO3. This leads to higher Eu-O bond polarizability and adds to the distortion in its environment around Eu3+ in BaTiO3:Eu compared with BaSnO3:Eu. This is responsible for the observed difference in the luminescence properties.