Abstract
We have studied the impact of TiO2 nano-wires (NWs) used as additives on inter-granular and intra-granular coupling of YBa2Cu3O7-d (noted YBCO or Y-123) superconductor. Series of YBCO/(TiO2)x with 0 ≤ x ≤ 1 wt% were made by solid-state reaction process. The crystal structure, morphology, microstructure and chemical compositions were methodically investigated using X-ray diffraction (XRD), scanning electron (SEM) and transmission electron (TEM) microscopes along with EDX system. XRD showed the obtaining of single YBCO orthorhombic phase for all samples. SEM and TEM observations revealed the occurrence of NWs dispersed among grains inducing inhomegenties and intergrowth of defect regions on YBCO/(TiO2) composite. The excess conductivity of YBCO/(TiO2)x superconductors were examined from the resistivity against temperature results. The examination indicated that the addition of TiO2 NWs led to the change in dimensional in the electrical properties and enhancement of physical parameters. The 0.1 wt% TiO2 added sample showed a dominance of 3D fluctuation regime and higher critical current density Jc(0) among all samples. AC-susceptibility were done using physical properties measurement system (PPMS). The detailed analysis confirmed the strengthening of inter-granular coupling of YBCO with the addition of small amount of TiO2 NWs. The inter-granular current density (Jc,inter(0)) was shown to be the highest in 0.1 wt% added sample.
•Impact of TiO2 nano-wires addition on inter- and intra-granular properties of Y-123.•No phase transition in Y-123 structure with the addition of TiO2 nano-wires.•Dominance of 3D fluctuation regime with addition of 0.1 wt% TiO2 nanowires.•Higher critical current density Jc(0) was obtained for 0.1 wt% TiO2 added sample.