The effect of process parameters on floating zone crystal growth of selected cuprates

Abstract Process parameters for floating zone crystal growth with optical heating were analyzed with special emphasis to the effect of external gas pressure. The cuprates are grown at low velocities ≤1 mm/h and with a traveling solvent floating zone enriched in CuO. Elevated oxygen pressure up to 15 MPa can affect phase equilibria and solidification modes, which enabled crystal growth of various novel compounds, which are not stable at normal pressure. Analyses of quenched zones suggest that crystals grow from oxygen depleted melts. Upon melting at the interface of the feed rod oxygen is released. Undesired formation of gas bubbles in the melt can be partly inhibited by growing under O 2 /Ar mixed gas atmosphere. Highly anisotropic antiferromagnetic ordering and strong effects of Ca doping in selected cuprates were revealed on single crystalline samples.