Growth mechanism of Sm2BaCuO5 crystal fiber

During the growth of SmBa2Cu3Oz superconductor thick film by a liquid phase epitaxy (LPE) process, some needle-like Sm2BaCuO5 crystal fibers were obtained. The long axis of the whiskers was in <001> direction, and the crystal faces appearing were (010), (110) and (210). Using Fourier-spectrum analysis, several characteristic peaks of [SmO7] polyhedra were detected in the melt quenched from the growth temperature. The growth mechanism of Sm2BaCuO5 crystal fibers could be explained from the viewpoint of the formation of the growth unit and the incorporation of the growth unit into different interfaces. Assembling of growth units [SmO7] into the (100) face has a comparatively strong bonding force, and the direction of this crystal face has a fast growth rate, thus the (100) face of the crystal disappears. The assembling of [SmO7] into (010) and (110) faces has a relatively small bonding force, and those crystal faces have a smaller growth rate. The <001> screw axis of Sm-211 crystal promotes the growth of the <001> direction; therefore, the long axis of the fiber is in the <001> direction.