Optical spectra of Yb3+ and Yb3+–Nd3+ interaction in Cs2NaNd0,4Yb0,6Cl6

Abstract

Interaction between octahedrally coordinated Nd3+ and Yd3+ in Cs2NaNd0,4Yb0,6Cl6 reduces the Nd3+ luminescence lifetime by roughly two orders of magnitude with respect to that found in Cs2NaNdCl6–·– Analysis of low temperature absorption and emission spectra reveals that the nonradiative Nd3+–Yb3+ energy transfer has to be assisted by lattice phonon emission, nevertheless the rate of the transfer is high in the 4–300K temperature region and attains 5.8×105s-1 at room temperature. A phase transition of Cs2NaNd0,4Yb0,6Cl6 between 12 and 13K is evidenced by abrupt change of both the spectra and lifetimes of Yb3+. Reduction of Yb3+ lifetime from 5.3ms to 150μs is at the transition from low symmetry phase to high symmetry phase is supposed to be associated with a three ion interaction which occurs in ordered lattice and disappears in low temperature disordered structure.