Synthesis of chalcogenide and pnictide crystals in salt melts using a steady-state temperature gradient
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Synthesis of Chalcogenide and Pnictide Crystals in Salt Melts Using a Steady-State Temperature Gradient D. A. Chareeva,b, O. S. Volkovac,b, N. V. Geringerd, A. V. Koshelevc,b, A. N. Nekrasova, V. O. Osadchiic,a, E. G. Osadchiia, and O. N. Filimonovac aInstitute
of Experimental Mineralogy, Russian Academy of Sciences, ul. Institutskaya 4, Chernogolovka, Moscow oblast, 142432 Russia b Institute of Physics and Technology, Ural Federal University, ul. Mira 19, Yekaterinburg, 620002 Russia cMoscow State University, Moscow, 119991 Russia d University of Dubna, ul. Universitetskaja 19, Dubna, 141980 Russia e-mail: [email protected] Received October 9, 2015
Abstract—Some examples of growing crystals of metals, alloys, chalcogenides, and pnictides in melts of halides of alkali metals and aluminum at a steady-state temperature gradient are described. Transport media are chosen to be salt melts of eutectic composition with the participation of LiCl, NaCl, KCl, RbCl, CsCl, AlCl3, AlBr3, KBr, and KI in a temperature range of 850–150°C. Some crystals have been synthesized only using a conducting contour. This technique of crystal growth is similar to the electrochemical method. In some cases, to exclude mutual influence, some elements have been isolated and forced to migrate to the crystal growth region through independent channels. As a result, crystals of desired quality have been obtained using no special equipment and with sizes sufficient for study under laboratory conditions. DOI: 10.1134/S1063774516030068
INTRODUCTION The general principles of growing crystals of metals, alloys, chalcogenides, and pnictides in melts of halides at a steady-state temperature gradient were described in [1]. The reaction vessel is made of quartz glass. Halides of alkali metals and aluminum can be used as transport media. The choice is determined by the melting temperature of the salt mixtures in use. In addition, the transport can be enhanced by applying a conducting contour. This technique of crystal growth is similar to the electrochemical method. To exclude mutual influence during migration, some elements can be isolated and forced to migrate to the crystal growth region through independent channels. The technique under consideration makes it possible to obtain crystals of necessary quality without any special equipment; the crystals have small sizes, which, nevertheless, are sufficient for study in laboratory. EXPERIMENTAL We used KCl, NaCl, CsCl, RbCl, NaBr, KBr, KI, anhydrous AlCl3 (Fluka, 98%), anhydrous FeCl3, anhydrous AlBr3, and other salts as components of salt melts. Crystallization water was removed from hygroscopic salts, such as NiCl2, by heating them in a smoky flame under evacuation. Hygroscopic lithium chlo-
ride was released from water during annealing in a drying box at 150°C for 24 h and then mixed with rubidium chloride. This mixture was also kept at 150°C. The charge for crystal growth was generally previously synthesized from elements (taken in the necessary ratios) in evacuated quartz glass ampoules [2]
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