The floating zone crystal growth of Ni, Co, Ni–Co, Ni–Zn, and Co–Zn ferrospinels under high oxygen pressure

Abstract

The apparatus and conditions for ferrospinel crystals growth by the floating zone melting are described. The URN-2-ZM apparatus equipped with a crystallization chamber for gas pressure up to 100 atm was used. The crystals of Ni and Co ferrospinels were grown at oxygen pressure ranging from 30 to 40 atm in order to eliminate formation of a vustite as a second phase in the composition. The Ni–Zn and Co–Zn ferrospinels were grown at oxygen pressure higher than 50 atm to suppress ZnO evaporation. The nearly stoichiometric compositions of ferrospinels were obtained using oxygen flow annealing after the growth.