Phases found at grain boundary of YBa2Cu3O7-d 50 nm films on SrTiO3 by enhanced anomalous scattering at O:K, Cu:L2,3 and Ba:M4,5 edges

TL;DR

This study detects a new phase at the grain boundary of YBa2Cu3O7-d films on SrTiO3 using enhanced anomalous scattering, revealing phase variations near the boundary and their temperature dependence.

Contribution

It introduces a novel application of enhanced anomalous scattering to identify phases at grain boundaries in high-temperature superconductor films.

Findings

A new phase is detected within 100 micrometers of the grain boundary.

Only the ortho-I phase is present far from the boundary, while both ortho-I and II are near the boundary.

The phase c0 remains constant across the superconducting transition.

Abstract

A new phase is detected within 100micrometers of 24 DEG ab grain boundary (GB) in YBa2Cu3O7-d 50 nm films on SrTiO3 by enhanced (001) anomalous scattering. Site identification and temperature dependence is interpreted using crystallographic weights to distinguish enhanced scattering from total electron yield and fluorescence spectra. The c-axis, c0 indicates that only ortho-I phase is present far from GB, both ortho-I and II phases are present near GB. The phase c0 is constant versus temperature across the transition to superconductivity.