Growth and characterization of Mn2+-activated magnesium aluminate spinel single crystals

Several concentrations of Mn2+-doped MgAl2O4 single crystals have been successfully grown using the micro-pulling-down (μ-PD) method. Due to their high melting temperature, the use of special Ir-Re crucibles was necessary. Because of the wide solubility range, the dependence of the behavior of the solid–liquid interface on the growth parameters was carefully studied to establish the growth conditions of stoichiometric MgAl2O4 spinel. Rod shaped 〈1 0 0〉 oriented single crystals of undoped and manganese doped MgAl2O4 spinel with 3 mm in diameter and a few centimeters in length were obtained in reducing argon atmosphere. The composition of Mn ions along the growth a-axis was controlled by the electron probe micro-analysis (EPMA). The optical transmission, crystallinity and thermal expansion of the grown crystals are investigated as well the annealing effect under oxidizing atmosphere will be detailed.