AC Susceptibility of BaZrO3 Nanoparticles Added YBa2Cu3O7−δ Superconductor Prepared via Coprecipitation Method

Abstract

In this work, magnetic properties of polycrystalline samples YBa2Cu3O7−δ added with x mol.% of BaZrO3 (BZO) nanoparticles (x = 0.0, 1.0, 2.0, 3.0, 5.0, and 7.0) were studied by AC susceptibility (ACS) measurement. The samples were prepared using coprecipitation (COP) method. X-ray diffraction (XRD) results showed that all the samples were composed of Y-123 as the major phase and Y-211 as the secondary phase. XRD peak of BZO was also observed in the samples added with BZO nanoparticles. The intensity of the peak became higher with increasing amount of BZO addition indicating the presence of increased amount of the unreacted nanoparticles in the samples. The refined lattice parameters indicated that all the samples have an orthorhombic crystal structure without the occurrence of orthorhombic-tetragonal phase transformation. Scanning electron microscopy (SEM) images showed that the samples have randomly distributed grains with irregular shape. The average grain size increased from 0.30 μ m for the pure sample to 0.50 μ m for the BZO addition of 7.0 mol.%. ACS measurement showed a slight decrease of onset critical temperature, Tc−onset (< 1 K) with BZO addition. Both phase lock-in temperature, Tcj, and coupling peak temperature, Tp, remained relatively unchanged for BZO addition up to 3.0 mol.%. Based on the Bean critical state model, the calculated intergranular critical current density, Jcm, for the pure sample is 1.88 A/cm2 at Tp = 84.8 K. For the sample added with 7.0 mol.% of BZO, Jcm at Tp = 83.6 K is 1.95 A/cm2.