Low-temperature high-pressure spectroscopy of lanthanum lutetium gallium garnet crystals doped with Cr3+ and Nd3+Article
Kamińska, A, Kaczor, P, Durygin, A et al. (2002). Low-temperature high-pressure spectroscopy of lanthanum lutetium gallium garnet crystals doped with Cr3+ and Nd3+
. PHYSICAL REVIEW B, 65(10), 1041061-1041068.
Kamińska, A, Kaczor, P, Durygin, A et al. (2002). Low-temperature high-pressure spectroscopy of lanthanum lutetium gallium garnet crystals doped with Cr3+ and Nd3+
. PHYSICAL REVIEW B, 65(10), 1041061-1041068.
Low-temperature luminescence measurements under high pressures in diamond-anvil cell of nonstoichiometric lanthanum lutetium gallium garnet (LLGG) doped with Cr3+ ions and nonintentionally with Nd3+ ions are reported. Three nonequivalent Cr3+ centers were found in the crystal using this technique. The results also reveal information about the electronic structure of different Cr3+ centers in those crystals. Cr3+ ions in a LLGG crystal experience a very low crystal field strength. The energy differences between the 4T2 and 2E levels are negative, and equal to about - 1100 cm-1 for two of those centers and about - 1500 cm-1 for the third one. The spectral results were corroborated by a theoretical analysis of the luminescence decay times as a function of pressure, which allowed one to establish the exact values of the crystal-field parameter Dq at ambient pressure for those centers. The crystal exhibits a large inhomogeneous broadening of the R lines, associated with nonstoichiometry. In addition to the Cr3+ luminescence also luminescence of Nd3+ ions was detected in the LLGG crystals. One of the Nd3+ luminescence lines, associated with the 4F3/2→4I9/2 transition, is strongly dependent on pressure, with a pressure coefficient equal to 0.96±0.02 cm-1/kbar, which makes this system interesting as a pressure gauge in the infrared region.
