Spin–lattice relaxation of Tl²⁺ ions in K₂SO₄ single crystals

Abstract

Spin-lattice relaxation times of T12+ ions in potassium sulphate single crystals were measured in the temperature range 1.5 to 25 OK a t a frequency of about 9 GHz by electron spinecho method. The relaxation is due to direct and Raman processes: TT1 = 1.02' + 3.3 x x 10-5T7. Deviations from the T;l-T7 dependence at high temperatures allow to estimate the Debye tempeature of K,SO, to 0 = 120 OK. The anomalous temperature dependence of the Raman processes is discussed.MeToRoM 3JIeKTPOHHOrO CIIHHOBOK'O 3xa Ha YaCTOTe Z 9 GHZ B ~~l a n a a o~e

Photoluminescence of KZnF3:Tl and KMgF3:Tl crystals

“…Such operators having a symmetry mode 4g = { 2 4u } have nonzero matrix elements on p electronic states. There are also other non-adiabatic mechanisms of electron-vibration coupling [19], which were considered as a possible reason for the anomalous temperature dependence of the spin-lattice relaxation time in K 2 SO 4 :Tl 2+ , observed in [20]. An effectiveness of state mixing due to non-adiabatic mechanisms increases with temperature, similar to other mechanisms with participation of phonons.…”

Spectroscopy of the ns1‐Centers in Ionic Crystals

“…No shf structure was observed, but changes in the lineshape and line positions observed by pulse annealing at RT were attributed to the departure of the charge compensating anion vacancy expected to be next to the T1' ion in the as-grown crystals. The spin-lattice relaxation (SLR) time 7'' of the T12+ centers in P-K,SO, has been measured in the 1.5 to 25 K temperature range by observing the spin-echo signal [165]. It exhibits a temperature dependence of the form (52) where T is the temperature, 0 = 120 K the Debye temperature, and f(H/T) is a factor describing the deviation from a pure Raman process, attributed [165] to the large hf splitting.…”

“…The spin-lattice relaxation (SLR) time 7'' of the T12+ centers in P-K,SO, has been measured in the 1.5 to 25 K temperature range by observing the spin-echo signal [165]. It exhibits a temperature dependence of the form (52) where T is the temperature, 0 = 120 K the Debye temperature, and f(H/T) is a factor describing the deviation from a pure Raman process, attributed [165] to the large hf splitting. T12 + centers produced by X-ray irradiation have been used as paramagnetic probes in studies of SPT, such as the paraelectric/ferroelectric transition in KD,PO,, Rb,H,PO,, and (NH,),SO, crystals [89,166 to 1691 and the paraelectric/antiferroelectric transition in NH,H2P0, crystals [170].…”