Fluctuation-induced conductivity analysis of Y2O3-layered YBCO single crystal

Abstract

In this work, a cylindrical YBa2Cu3O7-x (Y123) sample having 20 mm diameter and 8 mm height was prepared by the cold-seeding method using an Nd123 seed, and the crystal growth process was performed in an alumina crucible with a Y2O3 layer. The structural orientation of the specimens was measured by an X-ray diffractometer (XRD). As a result of the X-ray diffraction data, only (00 l) peaks were observed, indicating that all specimens are highly oriented with the c-axis perpendicular to the top surface. Resistivity measurements of a 1.5-mm-thick rectangular sample were performed by a standard four-probe method at temperatures between 60 and 100 K at a rate of 4 K/min using a Physical Properties Measurement System (PPMS) under various constant magnetic fields from 1 to 5 T with the magnetic field parallel to the c-axis, which is the direction of pressing into the zero-field cooling regime (ZFC). Fluctuation-induced conductivity analysis was performed to investigate the availability of the sample for technology. The analysis showed that the critical exponents were in agreement with theoretical values; thus, it was seen that superconducting properties of the sample were good and the 3D fluctuation was dominant. Because of the large c-axis coherence length (xi (c)(0)) and small anisotropy, the superconducting properties became better. Furthermore, the fluctuations were reduced, and it was understood that the effective availability of the sample in technology will be possible.