Growth of high-temperature phase KLu2F7 single crystals using quenching process

Abstract

KLu2F7 single crystals were grown by micro-pulling-down method. KLu2F7 has phase transition around 730°C, which is between melting temperature and room temperature. The high-temperature phase is monoclinic and the low temperature phase is orthorhombic. To keep the temperature of as-grown crystal above the phase transition temperature, the conventional carbon hot zone was modified, and its temperature gradient was investigated. Using the modified setup, KLu2F7 crystal with monoclinic (high temperature) phase was grown. After the growth procedure, the as-grown crystal was quenched to room temperature and it was found that the crystal keeps the monoclinic (high temperature) phase at room temperature.