In this paper, Cr-doped LiSrAlF 6 crystals are investigated using high-temperature Raman spectroscopy and the single-crystal Raman spectra of Cr:LiSrAlF 6 are analysed by factor group theory and comparison with other fluorides. The results indicate that Cr:LiSrAlF 6 is stable below its melting point; Raman peaks located at 561, 322 and 250 cm −1 are assigned to the A 1g modes of AlF 6 , SrF 6 and LiF 6 octachdra, respectively; with temperature increasing, Raman peaks associated with AlF 6

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... dra shift towards low frequencies, while LiF 6 and SrF 6 octahedra are temperatureinsensitive; around the crystal melting point, three new Raman peaks occur, which are associated with the AlF 6 octahedral chain structure. Finally, the microstructural evolution of Cr:LiSrAlF 6 from room temperature to its melting point is discussed based on its Raman spectra.