Photoluminescence studies of Mn4+ ions in YAlO3 crystals at ambient and high pressure

Detailed investigations of the photoluminescence properties of Mn4+ (3d(3)) ions in YAlO3 have been performed in the temperature range 10-600 K. The luminescence of Mn4+ ions due to the E-2 ->(4)A(2) transition consists of two zero-phonon lines (R lines) at 691.3 and 692.7 nm, which became visible only at low temperature, and their vibronic sidebands that cover the range of 660-740 nm. The thermal quenching of the luminescence intensity due to the non-radiative decay occurs at temperatures above 420 K. The temperature dependence of the luminescence decay time shows a quasi-linear decrease from t = 4.9 to 1.6 ms in the temperature range from 90 to 420 K (with a temperature coefficient -0.01 ms K-1) that makes YAlO3:Mn a potentially good phosphor for a fibre optic fluorescence thermometer in this temperature range. The high-pressure low-temperature luminescence measurements in a diamond-anvil cell reveal similar pressure coefficients for Mn4+ and Cr3+ dopant ions in YAlO3, equal to 1.16 cm(-1) kbar(-1) and 1.08 cm(-1) kbar(-1), respectively.