Effect of pressure on crystal-field transitions of Nd-doped YVO4

The effect of hydrostatic pressure on crystal field (CF) transitions of Nd-doped YVO4 has been studied by luminescence spectroscopy at T=5 K. Specifically, emissions from the F-4(3/2)(1) and F-4(3/2)(2) excited levels to the I-4(9/2) and I-4(11/2) multiplets have been measured within the stability range of the zircon-type phase (7.5 GPa). The observed redshift of the emissions with increasing pressure is attributed to the decrease of the Slater free-ion and spin-orbit parameters and an increase of the CF interaction as pressure increases. Results obtained for CF parameters are compared to those of Nd3+ in YAsO4 and YPO4. Satellite lines observed in YVO4:Nd can be assigned to Nd3+-Nd3+ ion pairs coupled by ferromagnetic exchange interaction; the exchange coupling increases with pressure