The PrAlO3−Pr2O3 Eutectic, its Microstructure, Instability, and Luminescent Properties

The praseodymium-aluminum perovskite−praseodymium oxide, PrAlO3−Pr2O3, eutectic has been studied. The growth of the eutectic by the micro-pulling down method is presented. The PrAlO3−Pr2O3 is not air-stable. The cause of the eutectic instability is the instability of the Pr2O3 phase. When exposed to air, the Pr2O3 phase changes into a new compound having a hexagonal unit cell with the lattice parameters a = b = 6.455(1) A, c = 11.322(4) A. The PrAlO3−Pr2O3 eutectic grows with a regular complex microstructure. The luminescence spectra are presented for both the eutectic and the new phase generated by exposing the eutectic to air.