The role of Ca in superconducting and magnetic properties of Y1-xCaxBa2Cu3O7 (x = 0.0-0.30)

TL;DR

This study investigates how calcium doping affects the structural, magnetic, and superconducting properties of YBa2Cu3O7, revealing that limited Ca doping improves grain connectivity and superconducting performance.

Contribution

It provides detailed analysis of Ca doping effects on structure and superconductivity, highlighting improved grain connectivity and performance at optimal doping levels.

Findings

Orthorhombicity decreases with Ca doping.

Superconducting transition temperature (Tc) decreases with Ca content.

Grain connectivity and size improve with Ca doping.

Abstract

We report the structural, superconducting, magnetic and granular properties of Y1-xCaxBa2Cu3O7; x = 0.0, 0.1, 0.2 and 0.3. Rietveld fitted X-ray diffraction data confirms the single phase formation for all the samples. The orthorhombicity of parent compound (x = 0.0) decreases and becomes closer to the tetragonal structure for higher Ca concentration. The superconducting transition temperature (Tc) decreases with increasing Ca content due to both over-doping and ensuing disorder in the superconducting CuO2 planes with Ca doping. DC susceptibility measurements reveal reduction of Meissner fraction with Ca doping, suggesting the flux pining effect. The AC susceptibility measurements reveal the enhancement of grain coupling with increasing Ca content in the system. The average grain size is found to increase with Ca doping. The Scanning Electron Microscopy (SEM) observations indicate better grain connectivity in terms of narrow grain boundaries for Ca doped samples. It is concluded that limited Ca doping enhances the superconducting performance of YBa2Cu3O7 system.