High pressure photoluminescence of Ce3+-doped (Y1.725Tb0.575Ce0.05Gd0.65)Al5O12

Photoluminescence of Y2.3-xTbxCe0.05Gd0.65Al5O12 (x = 0 and 0.575) has been measured at room temperature under high hydrostatic pressure. Broad-band emission peaked at 550 nm has been observed under 457 nm excitation, related to inter-configurational transition from the lowest state of excited electronic configuration 5d1 to the ground state of Ce3+ ions. Under excitation of 325 nm, mainly sharp-line luminescence has been observed related to 5D4 → 7F6, 5D4 → 7F5, 5D4 → 7F4 and 5D4 → 7F3 transitions in Tb3+ ions. Pressure induced red shift of the Ce3+ emission approximately equal to -20 cm-1/kbar, and much smaller shifts (approximately -1 cm-1/kbar) of the energies of sharp lines related to the Tb3+ luminescence have been observed.