Raman Study Of Hofe3(Bo3)(4) At Simultaneously High Pressure And High Temperature: P-T Phase Diagram

Raman spectra of a HoFe3(BO3)(4) crystal chip has been investigated at simultaneously high temperature and high pressure (up to 7.1GPa and 560K). On the basis of Raman analysis, the assignment to one of the two possible crystal phases has been made. The experimental p-T phase diagram of HoFe3(BO3)(4) was established. An increase in the pressure leads to an increase in the temperature of transition. The phase boundary equation was obtained. Neither triple points nor a phase with new symmetry was revealed in the phase diagram. A critical point with the temperature T=560K and the pressure p=2.53GPa was found. The nanocrystals with different shapes began to grow on crystal surface after reaching that point. The composition of new nanocrystals is identical to the composition of initial crystal. Copyright (c) 2017 John Wiley & Sons, Ltd.