Effect of structural changes on the zero-resistance transition temperature of La1Ba2Cu3O9−δ

Abstract

A series of high-$T_c$ ${\mathrm{La}}_1{\mathrm{Ba}}_2{\mathrm{Cu}}_3{\mathrm{O}}_{9-\delta }$ superconductors with zero resistance in the range from 27 to 69 K has been synthesized. The variance in $T_c$ is related to structural changes as observed through x-ray diffraction analysis. Of particular importance is the increase in the intensity of the $\frac{\mathrm{}\left(014\right)\mathrm{}}{\mathrm{}\left(005\right)\mathrm{}}$ superlattice peak with an increase in $T_c$, and evidence of orthorhombic shouldering for the highest-$T_c$ samples. The change in the intensity of the $\frac{\mathrm{}\left(014\right)\mathrm{}}{\mathrm{}\left(005\right)\mathrm{}}$ line can be explained by the movement of atomic positions brought about by oxygen deficiencies.