Scholarlink

<p>A novel high-entropy rare-earth barium copper oxide (HEREBCO) superconductor (Y<sub>0.2</sub>Pr<sub>0.2</sub>Nd<sub>0.2</sub>Sm<sub>0.2</sub>Gd<sub>0.2</sub>)Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-<i>δ</i></sub>, with a critical temperature of <i>T</i><sub>c</sub> = 41&#xa0;K, was synthesized by high-pressure torsion (HPT) and subsequent solid-state reaction. To examine the effect of severe plastic deformation on superconducting properties, the as-synthesized oxide was subsequently subjected to additional HPT processing. Structural characterization by X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy confirms a single-phase tetragonal <i>P</i>4/<i>mmm</i> structure, but HPT processing introduces a high density of oxygen vacancies specifically at the apical O(1) site, dense localized dislocations (~ 5 × 10<sup>16</sup>&#xa0;m<sup>−2</sup>) and ultrafine nanograins (&lt; 10&#xa0;nm). These defects severely distort the local atomic environment and reduce the density of hole carriers on the CuO<sub>2</sub> planes, as confirmed by synchrotron X-ray absorption spectroscopy and ultraviolet photoelectron spectroscopy. Consequently, the superconducting performance, measured by AC and DC magnetization, almost disappears after HPT processing. This study not only introduces HPT as a synthesis route for high-entropy oxide superconductors but also reveals a key difference from high-entropy alloy superconductors: HPT nanostructuring enhances superconductivity in metallic systems yet suppresses it in high-entropy oxides due to severe atomic distortion arising from both the high-entropy configuration and HPT-induced defects.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

New high-entropy rare-earth barium copper oxide superconductor via high-pressure torsion: significance of atomic distortion on superconductivity

  • 期刊论文

  • 发表日期：

    2026年8月3日

查看全文
  • Shivam Dangwal,
  • Alexy Bertrand,
  • Masaki Mito,
  • Kaveh Edalati

摘要

A novel high-entropy rare-earth barium copper oxide (HEREBCO) superconductor (Y0.2Pr0.2Nd0.2Sm0.2Gd0.2)Ba2Cu3O7-δ, with a critical temperature of Tc = 41 K, was synthesized by high-pressure torsion (HPT) and subsequent solid-state reaction. To examine the effect of severe plastic deformation on superconducting properties, the as-synthesized oxide was subsequently subjected to additional HPT processing. Structural characterization by X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy confirms a single-phase tetragonal P4/mmm structure, but HPT processing introduces a high density of oxygen vacancies specifically at the apical O(1) site, dense localized dislocations (~ 5 × 1016 m−2) and ultrafine nanograins (< 10 nm). These defects severely distort the local atomic environment and reduce the density of hole carriers on the CuO2 planes, as confirmed by synchrotron X-ray absorption spectroscopy and ultraviolet photoelectron spectroscopy. Consequently, the superconducting performance, measured by AC and DC magnetization, almost disappears after HPT processing. This study not only introduces HPT as a synthesis route for high-entropy oxide superconductors but also reveals a key difference from high-entropy alloy superconductors: HPT nanostructuring enhances superconductivity in metallic systems yet suppresses it in high-entropy oxides due to severe atomic distortion arising from both the high-entropy configuration and HPT-induced defects.