Photoluminescence studies of Mn⁴⁺ions in YAlO₃crystals at ambient and high pressure

Detailed investigations of the photoluminescence properties of Mn 4+ (3d 3 ) ions in YAlO 3 have been performed in the temperature range 10–600 K. The luminescence of Mn 4+ ions due to the 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 τ = 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 YAlO 3 :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 Mn 4+ and Cr 3+ dopant ions in YAlO 3 , equal to 1.16 cm −1 kbar −1 and 1.08 cm −1 kbar −1 , respectively.