[16a-317-1~8] 11.1 Fundamental properties

[16a-317-7] Magnetic anisotropy in dense MgO/Mg₂Si/MgB₂ nanocomposites

Katsuya Ueno¹, Yukihito Nagashima², Yusuke Seto¹, Megumi Matsumoto¹, Takahiro Sakurai¹, Hithoshi Ohta¹, Kazuyuki Takahashi¹, 〇Takashi Uchino¹ (1.Kobe Univ., 2.Nippon Sheet Glass)

Keywords:Josephson coupling, anisotropy, nanocomposite

Here, 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 ~26 K due to the construction of Josephson-coupled network, eventually leading to a near-zero resistance state at 17 K. We also show that the resulting Josephson coupling layer exhibits magnetic anistropy. This result is interpreted in terms of the pinning of the Josephson vortex in the direction perpendicular to the layer.