PrAlO₃−PrAl₁₁O₁₈ Eutectic: Its Microstructure and Spectroscopic Properties

Abstract

The praseodymium aluminum perovskite−praseodymium hexaluminate (PrAlO3−PrAl11O18) eutectic has been studied for the first time. It has been grown by the micro-pulling down method from a composition of 20.7% Pr2O3 and 79.3% Al2O3. The PrAlO3−PrAl11O18 eutectic tends to grow as a fibrous microstructure, with the PrAlO3 phase forming microfibers that are packed in a matrix of the PrAl11O18 phase. The eutectic has been grown with different pulling rates (p.r.’s): 0.15, 0.3, 0.45, 1, and 5 mm/min. The smallest microfibers were obtained with p.r. = 5 mm/min and are 300 nm in diameter. To the authors’ best knowledge, this is the first report of the crystalline phase of PrAl11O18. The absorption and luminescence spectra of the eutectic are presented. The fibrous/rodlike eutectic self-organized structure obtained in this work has the potential for application in modern photonics in the field of photonic crystals and/or metamaterials.