Journal of Crystal Growth, Vol.401, 844-848, 2014
Czochralski growth and characterization of MgAl2O4 single crystals
MgAl2O4 (MALO) single crystals were pulled by the Czochralski method in [111] direction. The crystals were doped with Co (0.06-0.6 at% (charge compositions)), because Co2+ ions in tetrahedral positions exhibit non-linear optical properties, and, currently, Co:MALO seems to be the best saturable absorber in the eye-safe region (ca. 1.5 mu m). By XRD powder technique a stoichiometric MALO was evidenced without admixtures of higher order spinels (MgAl4O7 and MgAl6O10). Also no excessive residual stresses have been discovered by different optical methods, and irrespective of the doping level we did not face any problem of cracking when cutting the crystals into wafers and other structures. In this work we have concentrated our efforts on investigation of thermal properties of MALO. Due to the 2nd order phase transition ca. 650 degrees C they seem to be of crucial importance in future thermal bonding of this material to the lasing host (Yb,Er-glass) expected just about this temperature. (C) 2013 Elsevier B. V. All rights reserved