Coherent interface structures and intergrain Josephson coupling in dense MgO/Mg2Si/MgB2 nanocomposites

Katsuya Ueno, Yukihito Nagashima, Yusuke Seto, Megumi Matsumoto, Takahiro Sakurai, Hitoshi Ohta, Kazuyuki Takahashi, Takashi Uchino

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Many efforts are under way to control the structure of heterointerfaces in nanostructured composite materials for designing functionality and engineering application. However, the fabrication of high-quality heterointerfaces is challenging because the crystal/crystal interface is usually the most defective part of the nanocomposite materials. In this work, we show that fully dense insulator (MgO)/semiconductor(Mg2Si)/superconductor(MgB2) nanocomposites with atomically smooth and continuous interfaces, including epitaxial-like MgO/Mg2Si interfaces, are obtained by solid phase reaction between metallic magnesium and a borosilicate glass. The resulting nanocomposites exhibit a semiconductor-superconducting transition at 36 K owing to the MgB2 nanograins surrounded by the MgO/Mg2Si matrix. This transition is followed by the intergrain phase-lock transition at ∼24 K due to the construction of Josephson-coupled network, eventually leading to a near-zero resistance state at 17 K. The method not only provides a simple process to fabricate dense nanocomposites with high-quality interfaces, but also enables to investigate the electric and magnetic properties of embedded superconducting nanograins with good intergrain coupling.

Original languageEnglish
Article number015102
JournalJournal of Applied Physics
Volume120
Issue number1
DOIs
Publication statusPublished - 2016 Jul 7
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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