Investigation of the Cr:LiSrAlF₆ crystal by high-temperature Raman spectroscopy

In this paper, Cr-doped LiSrAlF₆ crystals are investigated using high-temperature Raman spectroscopy and the single-crystal Raman spectra of Cr:LiSrAlF₆ are analysed by factor group theory and comparison with other fluorides. The results indicate that Cr:LiSrAlF₆ is stable below its melting point; Raman peaks located at 561, 322 and 250 cm^-1 are assigned to the A_1g modes of AlF₆, SrF₆ and LiF₆ octachdra, respectively; with temperature increasing, Raman peaks associated with AlF₆ octahedra shift towards low frequencies, while LiF₆ and SrF₆ octahedra are temperature-insensitive; around the crystal melting point, three new Raman peaks occur, which are associated with the AlF₆ octahedral chain structure. Finally, the microstructural evolution of Cr:LiSrAlF₆ from room temperature to its melting point is discussed based on its Raman spectra.