A Novel Technique for the Preparation of Textured YBa_{2}Cu_{3}O_{7-\delta} Superconductor

Authors: NAHEED KOUSER, SAADAT ANWAR SIDDIQI, ASGHARI MAQSOOD

Abstract: Textured samples having composition of YBa_{2}Cu_{3}O_{7-\delta} were prepared by using a novel technique of heating the samples in a thermal gradient which varies linearly between 930-950 ^oC over a distance of 5 cm. The samples were characterized by X-ray powder diffraction analysis, temperature dependent resistivity and magnetic susceptibility measurements, and scanning electron microscopy. XRD analysis shows that sample heated between 930-935 ^oC has tetragonal symmetry and all other three samples show orthorhombic symmetry. Samples heated in temperature gradient of 935-945 ^oC aligned along the c-axis. The orthorhombic samples exhibited zero resistance above 86K with short transition width and samples heated in the temperature range of 930-935 ^oC was non-superconducting down to 80 K. Susceptibility measurements also confirms the same T_{c} values for the superconducting samples. The orientation of crystals and alignment of grains was observed by SEM images and investigated by XRD patterns. The maximum texture alignment of the YBa_{2}Cu_{3}O_{7-\delta} superconducting grains is obtained in a thermal gradient of 935-945 ^oC.

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