Interface-enhanced superconductivity in multi-grain (FeSe)η(SrTiO3)1-η composites. (25th January 2021)

• Record Type: Journal Article
• Authors: Zhang, Huimin; Dong, Wenfeng; Meng, Qing-Long; Yin, Nan; Liu, Zhengmao; Lu, Xiaowei; Ge, Binghui; Li, Yuanzhao; Shi, Quan; Wang, Lili; Xue, Qi-Kun; Jiang, Peng; Bao, Xinhe
• Is Part Of: Superconductor science & technology. Volume 34:Number 3(2021)
• Publication Date: 2021-01-25
• Subjects: interface superconductivity -- FeSe/SrTiO3 -- multi-grain composite -- spark-plasma-sintering -- percolation; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/1361-6668/abd28f
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: Interface superconductivity, realized in multiple artificial crystalline heterostructures, is one of the most exciting directions to search for high-temperature superconductivity. In this work, we prepare bulk (FeSe) η (SrTiO3 )1− η multi-grain composites by a simple facile liquid-phase compaction method using a spark-plasma-sintering technique. Combining transmission electron microscopy/scanning electron microscopy and x-ray diffraction investigations, we demonstrate that the composites consist of micron-scale SrTiO3 grains surrounded by [001]-compressed β -FeSe grains. Transport measurements for the composites with FeSe mole fraction η > 0.06 reveal that two superconducting channels, one T c ∼ 13 K phase from FeSe/SrTiO3 interfaces and another T c ∼ 7 K phase from FeSe grains, cooperatively induce macroscopic superconducting behavior with isotropic upper critical fields above 40 T. This work points out a straightforward method to enhance T c in the multi-grain (FeSe) η (SrTiO3 )1− η composites by reducing the crystalline grains to nanoscale and finely tuning the stoichiometries of FeSe and SrTiO3 .