Growth of oriented C11(b)MoSi(2) bicrystals using a modified Czochralski technique

Oriented bicrystals of pure C11(b) MoSi2 have been grown in a tri-arc furna ce using the Czochralski technique. Two single-crystal seeds were used to i nitiate the growth. Each seed had the orientation intended for one of the g rains of the bicrystals, which resulted in a 60 degrees twist boundary on t he (1 1 0) plane. Seeds were attached to a water-cooled seed rod, which was pulled at 120 mm/h with the seed rod rotating at 45 rpm. The water-cooled copper hearth was counter-rotated at 160 rpm. Asymmetric growth ridges asso ciated with each seed crystal were observed during growth and confirmed the existence of a bicrystal. It was also found that careful alignment of the seeds was needed to keep the grain boundary from growing out of the boule. The resulting boundary was characterized by imaging and crystallographic te chniques in a scanning electron microscope. The boundary was found to be fa irly sharp and the misorientation between the grains remained within 2 degr ees from the misorientation between the seeds. (C) 1999 Elsevier Science B. V. All rights reserved.