Multiple superconducting phases and unusual enhancement of the upper critical field in Ute2

Dai Aoki; Fuminori Honda; Georg Knebel; Daniel Braithwaite; Ai Nakamura; De Xin Li; Yoshiya Homma; Yusei Shimizu; Yoshiki J. Sato; Jean Pascal Brison; Jacques Flouquet

doi:10.7566/JPSJ.89.053705

Multiple superconducting phases and unusual enhancement of the upper critical field in Ute2

Dai Aoki, Fuminori Honda, Georg Knebel, Daniel Braithwaite, Ai Nakamura, De Xin Li, Yoshiya Homma, Yusei Shimizu, Yoshiki J. Sato, Jean Pascal Brison, Jacques Flouquet

Research output: Contribution to journal › Article › peer-review

58 Citations (Scopus)

Abstract

We performed AC calorimetry and magnetoresistance measurements under pressure for H ∥ a-axis (easy-magnetization axis) in the novel heavy-fermion superconductor UTe2. Thanks to the thermodynamic information, multiple superconducting phases have been revealed under pressure and magnetic field. The ðH; TÞ phase diagram of superconductivity under pressure displays an abrupt increase of the upper critical field (Hc2) at low temperature and in the high field region, and a strong convex curvature of Hc2 at high temperature. This behavior of Hc2 and the multiple superconducting phases require a state for the superconducting order parameter more complex than a spin-triplet equal spin pairing. Above the superconducting critical pressure, Pc, we find strong indications that the possible magnetic order is closer to antiferromagnetism than to ferromagnetism.

Original language	English
Article number	053705
Journal	journal of the physical society of japan
Volume	89
Issue number	5
DOIs	https://doi.org/10.7566/JPSJ.89.053705
Publication status	Published - May 15 2020
Externally published	Yes

All Science Journal Classification (ASJC) codes

Physics and Astronomy(all)

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10.7566/JPSJ.89.053705

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title = "Multiple superconducting phases and unusual enhancement of the upper critical field in Ute2",

abstract = "We performed AC calorimetry and magnetoresistance measurements under pressure for H ∥ a-axis (easy-magnetization axis) in the novel heavy-fermion superconductor UTe2. Thanks to the thermodynamic information, multiple superconducting phases have been revealed under pressure and magnetic field. The {\dh}H; T{\TH} phase diagram of superconductivity under pressure displays an abrupt increase of the upper critical field (Hc2) at low temperature and in the high field region, and a strong convex curvature of Hc2 at high temperature. This behavior of Hc2 and the multiple superconducting phases require a state for the superconducting order parameter more complex than a spin-triplet equal spin pairing. Above the superconducting critical pressure, Pc, we find strong indications that the possible magnetic order is closer to antiferromagnetism than to ferromagnetism.",

author = "Dai Aoki and Fuminori Honda and Georg Knebel and Daniel Braithwaite and Ai Nakamura and Li, {De Xin} and Yoshiya Homma and Yusei Shimizu and Sato, {Yoshiki J.} and Brison, {Jean Pascal} and Jacques Flouquet",

note = "Funding Information: Acknowledgements We thank K. Machida, Y. Yanase, V. Mineev, S. Fujimoto, W. Knafo, K. Ishida, and Y. Tokunaga, for fruitful discussion. This work was supported by ERC starting grant (NewHeavyFermion), KAKENHI (JP15H05884, JP15H05882, JP15K21732, JP16H04006, JP15H05745, JP19H00646), and ICC-IMR. Publisher Copyright: {\textcopyright} 2020 The Physical Society of Japan.",

year = "2020",

month = may,

day = "15",

doi = "10.7566/JPSJ.89.053705",

language = "English",

volume = "89",

journal = "journal of the physical society of japan",

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TY - JOUR

T1 - Multiple superconducting phases and unusual enhancement of the upper critical field in Ute2

AU - Aoki, Dai

AU - Honda, Fuminori

AU - Knebel, Georg

AU - Braithwaite, Daniel

AU - Nakamura, Ai

AU - Li, De Xin

AU - Homma, Yoshiya

AU - Shimizu, Yusei

AU - Sato, Yoshiki J.

AU - Brison, Jean Pascal

AU - Flouquet, Jacques

N1 - Funding Information: Acknowledgements We thank K. Machida, Y. Yanase, V. Mineev, S. Fujimoto, W. Knafo, K. Ishida, and Y. Tokunaga, for fruitful discussion. This work was supported by ERC starting grant (NewHeavyFermion), KAKENHI (JP15H05884, JP15H05882, JP15K21732, JP16H04006, JP15H05745, JP19H00646), and ICC-IMR. Publisher Copyright: © 2020 The Physical Society of Japan.

PY - 2020/5/15

Y1 - 2020/5/15

N2 - We performed AC calorimetry and magnetoresistance measurements under pressure for H ∥ a-axis (easy-magnetization axis) in the novel heavy-fermion superconductor UTe2. Thanks to the thermodynamic information, multiple superconducting phases have been revealed under pressure and magnetic field. The ðH; TÞ phase diagram of superconductivity under pressure displays an abrupt increase of the upper critical field (Hc2) at low temperature and in the high field region, and a strong convex curvature of Hc2 at high temperature. This behavior of Hc2 and the multiple superconducting phases require a state for the superconducting order parameter more complex than a spin-triplet equal spin pairing. Above the superconducting critical pressure, Pc, we find strong indications that the possible magnetic order is closer to antiferromagnetism than to ferromagnetism.

AB - We performed AC calorimetry and magnetoresistance measurements under pressure for H ∥ a-axis (easy-magnetization axis) in the novel heavy-fermion superconductor UTe2. Thanks to the thermodynamic information, multiple superconducting phases have been revealed under pressure and magnetic field. The ðH; TÞ phase diagram of superconductivity under pressure displays an abrupt increase of the upper critical field (Hc2) at low temperature and in the high field region, and a strong convex curvature of Hc2 at high temperature. This behavior of Hc2 and the multiple superconducting phases require a state for the superconducting order parameter more complex than a spin-triplet equal spin pairing. Above the superconducting critical pressure, Pc, we find strong indications that the possible magnetic order is closer to antiferromagnetism than to ferromagnetism.

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Multiple superconducting phases and unusual enhancement of the upper critical field in Ute2

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