Lithium hydride single crystal growth by bridgman-stockbarger method using ultrasound

Abstract

Large lithium hydride single crystals, having the form of a double cone 80 mm in height and 40 mm in average diameter, have been grown by the modified Bridgman—Stockbarger method using ultrasound. The crystals have a perfect structure and differ from those grown earlier in the absolute absence of a small angle divergence of cleaved planes, the high stoichiometry and the small amount of uncontrolled impurities. To obtain the crystals, the necessary apparatus was designed and manufactured and optimal synthesis regimes have been found out. The quality was discovered to be greatly influenced by ultrasound. The LiH host was activated with various elements. The use of ultrasound gives rise to an almost uniform distribution of the activator over the volume. The X-ray analysis showed the samples to be monocrystalline and allowed the determination of the lattice parameters and the symmetry type of synthesized crystals to be made.