Temperature-dependence of Raman spectroscopy on the phase transition in LuBO3

Temperature-dependence of Raman spectroscopy on LuBO3 structure was performed in order to obtain information on structural changes induced by temperature evolution. The stability of the calcite phase and low-temperature vaterite phase of LuBO3 were both evaluated. For the sample with low-temperature vaterite phase, a strong first-order phase transition occurred during 1000–1200 °C, as indicated by the behavior of the Raman modes: the Raman bands split and new bands appear. The transition was associated with the B–O bond being broken in the cyclic B3O9 groups at high temperature, forming an open B3O9 group consisting of BO4 and BO3. Moreover, the influence of In3+ content on the structural characteristics of LuBO3 was investigated. It was found that the calcite phase of LuBO3 can be stabilized up to 1550 °C at least when the n(In)/n(Lu + In) ratio was more than 20 at%. The crystal growth and characterizations of Lu1−xInxBO3:Ce materials deserve further investigation.