High pressure and energy transfer in LaMgAl 11O 19:Cr 3+,Nd 3+

Abstract

The effect of high pressure on energy transfer from Cr 3+ to Nd 3+ in LaMgAl 11O 19:Cr 3+,Nd 3+ was studied up to 100 kbar. Experiments were performed in a NBS-type diamond anvil cell at room temperature. The energy transfer efficiency ( ε) was determined using the measured R line ( 2E→ 4A 2 transition) fluorescence lifetime from Cr 3+ in a sample with and without Nd 3+. The florescence lifetime τ for the R line for both samples increases non-linearly with pressure. We found that pressure has a significant effect on ε; it slowly increases linearly with pressure. The effect of high pressure on ε can be explained by the effect of high pressure on the inter-ionic distance R (compressibility k), the overlap between the 3d orbitals of the central Cr 3+ metal ion and the orbitals of the surrounding 2p ligands O 2−, the effective nuclear charge of Cr 3+, the spin–orbit coupling constant ξ and the energy of the 2E and 4T 2 levels. Good agreement between the theoretically predicted behavior of ε and experimental data was obtained. This leads to the conclusion that the model used can satisfactorily describe the effect of pressure on ε.