Effect of Lanthanum Substitution on Structure and Modulation in Bi₂Sr_2-xLa_xCaCu₂O_8+d (0≤x≤0.3) Superconducting Compound

Abstract

The effect of La substitution on the structure and its modulation in samples with a nominal composition of Bi2Sr2-xLaxCaCu2O8+d where 0≤x≤0.3 superconducting phase was investigated. The X-ray powder diffraction (XRPD) results showed an almost pure Bi-2212 phase, confirmed by the estimated amount of element concentration using dispersive energy X-ray spectroscopy (EDX). Scanning electron microscopy (SEM) micrographs showed a decrease of both crystallite size and connectivity when Lanthanum concentration increases. Le Bail refinement using the Jana2006 program gives a very good value of goodness of fit (GOF) factor. Also, the refinement reveals that for x=0.3 the orthorhombic cell transforms to the tetragonal one and the modulation vector q increases when increasing La concentration.