Large Bi-2212 single crystal growth by the floating-zone technique

TL;DR

This study investigates how growth velocity affects the formation of large, high-quality Bi-2212 single crystals using the floating-zone technique, emphasizing the importance of a stable planar growth front.

Contribution

It demonstrates the critical growth velocity threshold for maintaining a stable planar interface and successfully produces large, high-quality Bi-2212 single crystals with detailed characterization.

Findings

Stable planar growth front is essential for large crystal size.

Growth velocity above 0.25 mm/h causes interface breakdown.

Crystals up to 50x7.2x7 mm3 were obtained with good quality.

Abstract

Effects of the growth velocity on the crystal growth behavior of Bi_2Sr_2Ca_1Cu_2O_x (Bi-2212) have been studied by floating zone technique. The results show that a necessary condition for obtaining large single crystals along the c-axis is that the solid-liquid interface of a growing rod maintains a stable planar growth front. The planar liquid-solid growth interface tends to break down into a cellular interface, while the growth velocity is higher than 0.25 mm/h. Single crystals of up to 50x7.2x7 mm3 along the a-, b- and caxes have been cut in a 7.2 mm diameter rod with optimum growth conditions. Tconset is 91 K measured by magnetic properties measurement system (MPMS) for as-grown crystals. Optical polarization microscope and neutron diffraction show that the quality of the single crystals is good.