Novel phase diagram of superconductivity and ferromagnetism in UGe 2

A 73Ge-NQR study under high pressure

Y. Kitaoka, H. Kotegawa, A. Harada, Shinji Kawasaki, Y. Kawasaki, Y. Haga, E. Yamamoto, Y. Onuki, K. M. Itoh, E. E. Haller, H. Harima

Research output: Contribution to journalArticle

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Abstract

We report on the pressure-induced novel phases of ferromagnetism (FM) and superconductivity (SC) in the itinerant ferromagnet UGe2 through 73Ge-NQR measurements under pressure (P). The P dependence of the NQR spectrum points to a first-order transition from strongly to weakly polarized ferromagnetic phases (SP and WP) around a critical pressure of P*c ∼ 1.2 GPa. Furthermore, it shows the phase separation into the ferromagnetic and paramagnetic phases around Pc ∼ 1.6 GPa. SC exhibiting a maximum value of the superconducting transition temperature Tsc ∼ 0.7 K at P*c ∼ 1.2 GPa was found to take place in connection with a P-induced first-order transition from SP to WP. The measurement of nuclear spin lattice relaxation rate 1/T1 has probed the ferromagnetic transition, exhibiting a peak at the Curie temperature as well as a decrease without the coherence peak below Tsc. These results reveal the uniformly coexistent phase of FM and unconventional SC with a line-node gap. Around Pc where the FM disappears, it is shown that SC occurs under the background of FM, but not in the paramagnetic phase. We remark on an intimate interplay between the onset of SC and the underlying electronic state for SP and WP.

Original languageEnglish
JournalJournal of Physics Condensed Matter
Volume17
Issue number11
DOIs
Publication statusPublished - Mar 23 2005
Externally publishedYes

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Ferromagnetism
Superconductivity
ferromagnetism
Phase diagrams
superconductivity
phase diagrams
Spin-lattice relaxation
critical pressure
Electronic states
Curie temperature
Phase separation
spin-lattice relaxation
nuclear spin
Superconducting transition temperature
transition temperature
electronics

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Novel phase diagram of superconductivity and ferromagnetism in UGe 2 : A 73Ge-NQR study under high pressure. / Kitaoka, Y.; Kotegawa, H.; Harada, A.; Kawasaki, Shinji; Kawasaki, Y.; Haga, Y.; Yamamoto, E.; Onuki, Y.; Itoh, K. M.; Haller, E. E.; Harima, H.

In: Journal of Physics Condensed Matter, Vol. 17, No. 11, 23.03.2005.

Research output: Contribution to journalArticle

Kitaoka, Y, Kotegawa, H, Harada, A, Kawasaki, S, Kawasaki, Y, Haga, Y, Yamamoto, E, Onuki, Y, Itoh, KM, Haller, EE & Harima, H 2005, 'Novel phase diagram of superconductivity and ferromagnetism in UGe 2: A 73Ge-NQR study under high pressure', Journal of Physics Condensed Matter, vol. 17, no. 11. https://doi.org/10.1088/0953-8984/17/11/030
Kitaoka, Y. ; Kotegawa, H. ; Harada, A. ; Kawasaki, Shinji ; Kawasaki, Y. ; Haga, Y. ; Yamamoto, E. ; Onuki, Y. ; Itoh, K. M. ; Haller, E. E. ; Harima, H. / Novel phase diagram of superconductivity and ferromagnetism in UGe 2 : A 73Ge-NQR study under high pressure. In: Journal of Physics Condensed Matter. 2005 ; Vol. 17, No. 11.
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