Studies on strongly correlated electron superconductors coexisting and/or competing with magnetism

2015 Fiscal Year Final Research Report

• Project/Area Number: 23244075
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Condensed matter physics II
• Research Institution: Kyoto University
• Principal Investigator: ISHIDA Kenji 京都大学, 理学(系)研究科(研究院), 教授 (90243196)
• Project Period (FY): 2011-04-01 – 2016-03-31
• Keywords: 超伝導 / 強磁性超伝導 / 磁気共鳴 / 鉄系超伝導 / 強磁性ゆらぎ / 超伝導発現機構

Outline of Final Research Achievements

We have studied the relationship between superconductivity and magnetism on strongly correlated electron superconductors located near magnetic phase with nuclear magnetic resonance (NMR)/ nuclear quadrupole resonance (NQR). In this research project, we have focused on ferromagnetic superconductor UCoGe and iron-based superconductor BaFe2(As1-xPx)2 and investigated the coexistence of superconductivity and magnetic ordering and the role of the magnetic fluctuations for the occurrence of superconductivity from the microscopic point of view.
We obtained following results on UCoGe: 1)Superconductivity and magnetism coexist microscopically in UCoGe. 2)From the nuclear spin-lattice relaxation rate 1/T1 measurements in three directions and under various magnetic fields, Ising ferromagnetic fluctuations in UCoGe play an important role in superconductivity, which presumably pairing glue for superconductivity. 3) Thus, the pairing symmetry of UCoGe would be spin triplet.

Free Research Field

数物系科学