0000000000240070
AUTHOR
J. Trokss
Colour centres in LiBaF3 crystals
Abstract The origin of the absorption bands in LiBaF 3 created by X-ray irradiation at RT has been investigated. It is found that three absorption bands at 270, 320 and 430 nm represent different electron transitions within a radiation defect effectively created in LiBaF 3 single crystals. Following the Mollwo–Ivey relation we discuss investigations of optical dichroism, magnetic optical dichroism, as well as the assumptions regarding the accumulation kinetics of these absorption bands, the F centre being the main radiation defect created by X-rays in undoped LiBaF 3 crystals at RT.
Radiation Defects in LiBaF3 Perovskites
We investigated the electron paramagnetic resonance (EPR), recombination afterglow, thermostimulated luminescence (TSL) and absorption of LiBaF3 perovskites crystals X-irradiated at 80 K The self-trapped hole centre VK(F2-) oriented along the [110] axis and electron F type (FA) centres are identified. X-irradiation at temperatures below 200 K results in creation of a long-term temperature-independent afterglow-tunnelling luminescence (TL), with main emission bands at 300, 370 nm and 430 nm. The short wavelength TL bands are associated with the tunnelling recombination of the F type centre with the VK centre. The thermal stability of VK centre is estimated to be about 130 K.
Colour centres in LiBaF3
Abstract The X-ray-induced optical absorption (OA) and the spectra of magnetic circular dichroism (MCD) followed by optically detected EPR (ODEPR) have been investigated in undoped LiBaF3 crystals. According to ODEPR, the absorption bands in the spectral region 470–770 nm correspond to the F-type centres, whereas the absorption band at 420 nm is assigned to the hole centres. The redistribution of electrons to the thermal more stable F-type centres indicates that all types of colour centres are annealed in the course of the thermal release of electrons from F-type centres, accompanied by a thermostimulated luminescence.