Emission from BaTiO3:Pr3+ controlled by ionic radius of added trivalent ion

Emission enhancement from BaTiO3:Pr3+ by addition of trivalent ion under excitation above the fundamental absorption edge of BaTiO3 host crystals has been investigated. In this system, energy transfer occurs from BaTiO3 to Pr3+. Emission of Pr3+ is intensified by addition of small trivalent ions, e.g., Yb3+ or Sc3+, which substitutes for Ti4+ site, while it is hardly changed by addition of La3+ or Nd3+, which is larger in the ionic radius and substitutes for Ba2+ site. Moreover, smaller difference in ionic radius between the added trivalent ions and Ti4+ induces larger ratio of D-1(2)-->H-3(4) emission intensity to P-3(0)-->H-3(4) emission intensity. Addition of Ga3+ gives the largest ratio and the D-1(2)-->H-3(4) emission intensity among the trivalent ions. These observations demonstrate that one of the origins of the emission enhancement is charge compensation of Pr3+ at the Ba2+ site by the trivalent ion substituting for Ti4+ around the Pr3+, and the emission from BaTiO3:Pr3+ can be controlled by the ionic radius of the added trivalent ion. (C) 2002 American Institute of Physics.