Spectroscopic properties of Cr³⁺In RbCdF₃

Abstract

A spectroscopic study of chromium-doped RbCdF3 crystals has been performed. Cubic, tetragonal and trigonal Cr3+ centres have been detected by EPR measurements. The spin Hamiltonian parameters of trigonal and one type of tetragonal Cr3+ ions, not previously reported, have been found to be: g/sub ///=1.969, gperpendicular to =1.971 and mod D mod =0.1576 cm-1 for the trigonal centre and g/sub ///=1.970, gperpendicular to =1.972 and mod D mod =0.0722 cm-1 for the tetragonal one. Crystal field and Racah parameters of cubic Cr3+ derived from the optical absorption spectrum are: Dq=1420 cm-1, B=800 cm-1 and C=3290 cm-1. Photoluminescence has been measured at different temperatures and the phonon structure observed at 15 K has been associated with different Cr3+ centres. The lifetimes of the emitting levels of cubic and trigonal Cr3+ ions measured at 15 K have been found to be 470 mu s and 220 mu s respectively. At 300 K the lifetime of cubic centres decreases to about 180 mu s. No direct influence of the phase transition on the optical properties of Cr3+ ions, when the authors go through the transition temperature, has been detected.