ADDITION OF KNO3 ON YBCO-123 IN ENHANCING THE STRUCTURAL AND MAGNETIC PROPERTIES VIA THERMAL TREATMENT METHOD

Abstract

Bulk superconductor of YBa₂Cu₃O_7−δ (Y-123) was synthesized by using thermal treatment method. Small amounts (0, 0.1, 0.2 and 0.3 mole) of potassium nitrate (KNO₃) was added into Y-123 system. The sequel of KNO₃ addition on its critical temperature (T_c), phase formation and the microstructure properties were studied. A characterization on the structural properties by means of the X-ray diffraction (XRD) has been investigated. All samples showed an orthorhombic crystal structure with the main phase of Y-123 and Y-211 as a secondary phase. The volume fraction of pure Y 123 is 93.7%. As KNO₃ was added, the percentage of volume fraction decreases. Sample of x = 0.2 give the highest percentage among the added samples with the value of 87.1 %. From electrical properties, the T_c value has been enhanced as KNO₃ was added. The highest T_c value (92.7 K) is verified for the sample x = 0.2 with homogeneous grains connectivity. The Y-123 microstructure of the grain growth increases and more homogeneous as KNO₃ was promoted in the system. All in all, these results suggest that the addition of KNO₃ give an enhancement in superconducting properties particularly for the addition of x = 0.2 mole.