Y358 against Y123 structural phase in a Y-based superconductor

TL;DR

This study experimentally characterizes the Y358 phase in a Y-based superconductor, comparing it to Y123, and clarifies their structural and superconducting property differences.

Contribution

It provides the first detailed experimental characterization of Y358, including its structure and transition temperature, contrasting it with Y123.

Findings

Y358 has a transition temperature of 105K.

Y358 contains three CuO2 planes and two CuO chains.

Y358's structure matches density functional theory predictions.

Abstract

We report an experiment in which two distinct superconducting phase YBa2Cu3O7 (Y123) and Y3Ba5Cu8O18 (Y358) coexisted. This enabled us to characterize the recently introduced Y358 phase in contrast to the Y123 phase, thus to resolve some discrepancies reported in associated properties of Y358. Specifically, our experiment indicates the transition temperature TCmid=105K and 94K for Y358 and Y123, respectively, and that Y358 has three CuO2 planes and two CuO chains, with Pmm2 symmetry and lattice parameter (a,b,c)=(3.845,3.894,31.093){\AA}, in agreement with density functional theory predictions for this specific structure.