Scanning micro X-ray diffraction unveils the distribution of oxygen chains nano-puddles in YBa2Cu3O6.33

TL;DR

This study uses scanning micro X-ray diffraction to visualize and analyze nanoscale oxygen chain puddles in YBa2Cu3O6.33, revealing their size, distribution, and role in superconductivity at low doping levels.

Contribution

It introduces a novel imaging method to map oxygen chain fragments and their organization in YBa2Cu3O6.33, providing new insights into their nanoscale distribution and effects on superconductivity.

Findings

Nanoscale striped puddles with Ortho-II structure identified

Puddle sizes range from 2 to 9 nanometers

Superconductivity occurs in a network of oxygen-ordered patches

Abstract

Oxygen chain fragments are known to appear at the insulator to superconductor transition (SIT) in YBa2Cu3O6+y. However the self organization and the size distribution of oxygen chain fragments is not known. Here we contribute to fill this gap, using scanning micro X ray diffraction which is a novel imaging method based on advances in focusing synchrotron radiation beam. This novel approach allows us to probe both real-space and k-space of a high-quality YBa2Cu3O6.33 single crystals with Tc=7K. We report compelling evidence for nanoscale striped puddles, with Ortho-II structure, made of chain fragments in the basal Cu(1) plane with local oxygen concentration 0.5. The size of the Ortho-II puddles spans a range between 2 and 9 nanometers. The real space imaging of Ortho-II puddles granular network shows that superconductivity, at low hole-doping regime, occurs in a network of nanoscale oxygen ordered patches, interspersed with oxygen depleted regions. The manipulation by thermal treatments of the striped Ortho II puddles has been investigated focusing on the spontaneous symmetry breaking near the order to disorder phase transition at 350 K.