Nested antiferromagnetic spin fluctuations and non-Fermi-liquid behavior in electron-doped CeCoNiIn

Sakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Zhu, J.-X.*; Ronning, F.*; Thompson, J. D.*; Kotegawa, Hisashi*; To, Hideki*; Suzuki, Kohei*; Oshima, Yoshiki*; et al.

Physical Review B, 106(23), p.235152_1 - 235152_8, 2022/12

https://doi.org/10.1103/PhysRevB.106.235152

We investigate the electronic state of Ni-substituted CeCoNiIn by nuclear quadrupole and magnetic resonance (NQR/NMR) techniques. The heavy fermion superconductivity below K for is suppressed by Ni substitutions, and reaches zero for . The In NQR spectra for and 0.25 can be explained by simulating the electrical field gradient that is calculated for a virtual supercell with density functional theory. The spin-lattice relaxation rate indicates that Ni substitution weakens antiferromagnetic correlations that are not localized near the substituent but instead are uniform in space. The temperature () dependence of for shows a maximum around K and decreases toward almost zero when temperature is further reduced as if a gap might be opening in the magnetic excitation spectrum; however, the magnetic specific heat and the static magnetic susceptibility evolve smoothly through with a dependence. The peculiar T dependence of and non-Fermi-liquid specific heat and susceptibility can be interpreted in a unified way by assuming nested antiferromagnetic spin fluctuations in a quasi-two-dimensional electronic system.

NMR studies on antiferromagnetic fluctuation in UPt

Aoyama, Taisuke*; Kotegawa, Hisashi*; To, Hideki*; Kimura, Noriaki*; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika*

Physica B; Condensed Matter, 570, p.349 - 351, 2019/10

https://doi.org/10.1016/j.physb.2018.02.031

Anisotropic magnetic fluctuations in ferromagnetic superconductor UGe; Ge-NQR study at ambient pressure

Noma, Yuichiro*; Kotegawa, Hisashi*; Kubo, Tetsuro*; To, Hideki*; Harima, Hisatomo*; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika*; Ito, Kohei*; Haller, E. E.*; et al.

Journal of the Physical Society of Japan, 87(3), p.033704_1 - 033704_5, 2018/03

https://doi.org/10.7566/JPSJ.87.033704

Field-induced phenomena in ferromagnetic superconductors UCoGe and URhGe

Aoki, Dai*; Taupin, M.*; Paulsen, C.*; Hardy, F.*; Taufour, V.*; Kotegawa, Hisashi*; Hassinger, E.*; Malone, L.*; Matsuda, Tatsuma; Miyake, Atsushi*; et al.

Journal of the Physical Society of Japan, 81(Suppl.B), p.SB002_1 - SB002_6, 2012/12

https://doi.org/10.1143/JPSJS.81SB.SB002

Strong longitudinal magnetic fluctuations near critical end point in UCoAl; A Co-NMR study

Nohara, Hiroki*; Kotegawa, Hisashi*; To, Hideki*; Matsuda, Tatsuma; Yamamoto, Etsuji; Haga, Yoshinori; Fisk, Z.; Onuki, Yoshichika; Aoki, Dai*; Flouquet, J.*

Journal of the Physical Society of Japan, 80(9), p.093707_1 - 093707_4, 2011/09

https://doi.org/10.1143/JPSJ.80.093707

Muon spin rotation study of magnetism in multilayer HgBaCaCuO superconductor

Tokiwa, Kazuyasu*; Mikusu, Satoshi*; Higemoto, Wataru; Nishiyama, Kusuo*; Iyo, Akira*; Tanaka, Yasumoto*; Kotegawa, Hisashi*; Mukuda, Hidekazu*; Kitaoka, Yoshio*; Watanabe, Tsuneo*

Physica C, 460-462(2), p.892 - 895, 2007/09

https://doi.org/10.1016/j.physc.2007.03.187

Zero- and longitudinal-field muon-spin rotation (ZF-SR and LF-SR) measurements were carried out on a multi-layered HgBaCaCuO (Hg-1245) superconductor with of 108 K. With decreasing temperature, the observed ZF-SR function changed from a Gaussian-type to an exponential-type below 60 K and zero field muon precession was also observed below 45 K. These SR signals are attributed to the development of the antiferromagnetic ordering in inner CuOplanes with a low carrier concentration. These results seem to indicate clear evidence that antiferromagnetism microscopically coexists with superconductivity in the Hg-1245 superconductor below 60 K.

Cooperative phenomenon of ferromagnetism and unconventional superconductivity in UGe; A Ge-NQR study under pressure

Harada, Atsuyuki*; Kawasaki, Shinji*; Kotegawa, Hisashi*; Kitaoka, Yoshio*; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika; Ito, Kohei*; Haller, E. E.*; Harima, Hisatomo*

Journal of the Physical Society of Japan, 74(10), p.2675 - 2678, 2005/10

https://doi.org/10.1143/JPSJ.74.2675

no abstracts in English

NMR study of Zn- and Ni-substitution effect in heavy fermion superconductor CeCoIn

Sakai, Hironori; Tokunaga, Yo; Haga, Yoshinori; Kambe, Shinsaku; Zhu, J.-X.*; Ronning, F.*; Ramakrishna, S. K.*; Reyes, A. P.*; Kotegawa, Hisashi*; To, Hideki*; et al.

no journal, , 

In heavy fermion superconductor CeCoIn, slight Zn substitutions for In atoms induce antiferromagnetism, while slight Ni substitutions for Co atoms suppress superconductivity. The both substituted CeCoIn exhibit non- fermi-liquid behaviors near the phase boundaries which have been detected by magnetization and specific heat measurements. We have performed NMR experiments in these systems to investigate the microscopic effects by substituents. We will discuss about the spin fluctuations near the boundaries by NMR relaxation rates.

Microscopic study of Ni and Zn substitution effects in heavy fermion superconductor CeCoIn

Sakai, Hironori; Tokunaga, Yo; Haga, Yoshinori; Kambe, Shinsaku; Ronning, F.*; Zhu, J.-X.*; Thompson, J. D.*; Kotegawa, Hisashi*; To, Hideki*; Suzuki, Kohei*; et al.

no journal, , 

Heavy fermion superconductor CeCoIn is considered as a quantum critical antiferromagnetic material. When the In elements are slightly substituted by Zn elements, a long-range antiferromagnetism is induced. On the other hand, slight Sn substitutions make the system step away from the quantum critical point. In the case of Zn substitutions, heterogeneity of antiferromagnetic area in the matrix of heavy fermion state has been microscopically confirmed by NQR measurements. In the case of Ni substitutions for the Co elements, the NQR result appears to be the same as in Sn substituted system.