Elucidation and search for new quantum states in ferromagnetic quantum critical endpoint

2014 Fiscal Year Final Research Report

• Project/Area Number: 24340085
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: Kobe University
• Principal Investigator: KOTEGAWA Hisashi 神戸大学, 理学(系)研究科(研究院), 准教授 (30372684)
• Co-Investigator(Kenkyū-buntansha): TOU Hideki 神戸大学, 大学院理学研究科, 教授 (60295467)
• Co-Investigator(Renkei-kenkyūsha): SUGAWARA Hitoshi 神戸大学, 大学院理学研究科, 教授 (60264587) ; MATSUDA Tatsuma 首都大学東京, 大学院理工学研究科, 准教授 (30370472)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 強磁性 / 量子臨界点 / メタ磁性 / 超伝導 / 圧力

Outline of Final Research Achievements

We have investigated microscopic states and details of magnetic fluctuation for UCoAl and URhGe which possess a ferromagnetic quantum critical endpoint, by means of nuclear magnetic resonance (NMR). As a result, we have succeeded to observe a development of strong magnetic fluctuations in the vicinity of the quantum critical endpoint of both compounds. The observed magnetic fluctuations are conjectured to play important role for field-induced superconductivity in URhGe.
We have also found a metamegnetic transition which appears under pressure in ferromagnet CeRuPO, and ferromagnetic critical point in CeIr3B2. For helimagnet CrAs, we have found pressure-induced superconductivity. From nuclear quadrupole resonance (NQR) measurements, we have obtained the results indicating that superconductivity in CrAs is mediated by magnetic fluctuations, and that CrAs is the first Cr-based unconventional superconductor.

Free Research Field

低温物性