Study of Structural Modification and Fluctuation Induced Electrical Conductivity in $$\text {YBa}_{2}\text {Cu}_{3}\text {O}_{7-y}+x \text {BaSnO}_{3}$$ YBa 2 Cu 3 O 7 - y + x BaSnO 3 Superconductor Composite

Abstract

A series of $$(1-x) \text {YBa}_{2}\text {Cu}_{3}\text {O}_{7-y} + x \text {BaSnO}_{3 }(x = 0.0, 0.1, 0.3, 0.5, 1.0, 2.5, 5.0\,\text {wt}{\%})$$ samples were prepared using the solid-state reaction method. XRD graphs confirm the orthorhombic structure in pristine as well as in composite samples. Raman spectra show the presence of all the vibration modes in pure as well as in the composite samples. In addition, some defect-induced modes have also appeared in the higher weight % BSO-added sample, and no loss of apical oxygen O(4) at 500 cm $$^{-1}$$ occurs due to BaSnO $$_{3}$$ (BSO) addition. Microstructural analysis reveals the unchanged grain size with the incorporation of dielectric BSO particles in the YBCO matrix. Superconducting transition temperature determined from standard four-probe method decreases with the increase of BSO wt%. Excess conductivity fluctuation analysis using Aslamazov–Larkin model fitting reveals transition of two dominant regions (2D and 3D) above $$T_\mathrm{c}$$ . 2D to 3D crossover temperature i.e. Lawrence–Doniach temperature that demarcates dimensional nature of fluctuation inside the grains is influenced by BSO incorporation in YBCO matrix.