Growth and raman scattering of aluminium gallium orthophosphate piezoelectric crystals

A new series of non-ferroelectric crystals, the piezoelectric solid solution aluminium gallium orthophosphate Al1-xGaxPO4 (AGP, 0 < x < 1) system has been successfully developed by a hydrothermal method. The AGP crystal with x = 0.10 shows a phase transition temperature Tα−β = 587 ± 3 °C with a cell parameters a = b = 0.49386(3) and c = 1.09563(2) nm. Raman spectra including directional dispersion in AGP are similar to those from α-AIPO4 and α-quartz crystals, indicating all of them belong to an isomorphic family, the short-range interaction being dominant in AGP. Comparison with α-AIPO4 crystals, there exists an apparent red shift of the mode frequency and a smaller TO/LO mode splitting of the E species in the AGP crystals.