Uniaxial pressure effect on quantum critical phenomenon of quasicrystal

2014 Fiscal Year Final Research Report

• Project/Area Number: 25610094
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics II
• Research Institution: Nagoya University
• Principal Investigator: DEGUCHI Kazuhiko 名古屋大学, 理学(系)研究科(研究院), 助教 (40397584)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: 量子臨界現象 / 準結晶 / 磁性 / 強相関電子系 / 極低温 / 高圧

Outline of Final Research Achievements

One of the purposes of this research is　to search new physical phenomena in the magnetic quasicrystal of a strongly correlated electron system with Tsai-type clusters. First, we report the emergence of bulk superconductivity in Au-Ge-Yb approximants (AGY(I) and AGY(II)) below 0.68 and 0.36 K, respectively. This is the first observation of superconductivity in Tsai-type crystalline approximants of quasicrystals. We also present a structure model refined by Rietveld analysis for X-ray diffraction data. The Tsai-type cluster center is occupied by Au and Ge ions in the former approximant, and by an Yb ion in the latter. For magnetism, the latter system shows a larger magnetization than the former. To explain this observation, we propose a model that the cluster-center Yb ion is magnetic.

Free Research Field

強相関電子系