Concentration and temperature dependence of Nd3+ luminescence in LaGaO3

The Nd3+ luminescence in La1-xNdxGaO3 ceramics was measured at temperatures from 10 to 500 K for different neodymium dopant concentrations. The quantum efficiency of the F-4(3/2) emission is close to unity and temperature independent for x less than or equal to 0.01. The emission decay follows the exponential law with lifetime of approximate to 225 mu s at 300 K. As concentration increases the evolution of the emission intensity with time after pulsed excitation is no longer exponential. Cross relaxation and energy migration effects are proposed to explain this concentration quenching. The energies of the Nd3+ Stark levels are slightly changed and the emission lifetimes remain unchanged through the LaGaO3 first-order phase transition from orthorhombic to rhombohedral structure. This is in contrast with the large increase in the critical temperature produced by even modest amounts of Nd3+ ions. (C) 2000 Elsevier Science B.V. All rights reserved.