Absence of Meissner State and Robust Ferromagnetism in the Superconducting State of UCoGe: Possible Evidence of Spontaneous Vortex State

被引：30

作者：

Deguchi, Kazuhiko ^{[1
]}

Osaki, Eisuke ^{[1
]}

Ban, Seiko ^{[1
]}

Tamura, Nobuyuki ^{[1
]}

Simura, Yasuyuki ^{[2
]}

Sakakibara, Toshiro ^{[2
]}

Satoh, Isamu ^{[3
]}

Sato, Noriaki K. ^{[1
]}

机构：

[1] Nagoya Univ, Grad Sch Sci, Dept Phys, Nagoya, Aichi 4648602, Japan

[2] Univ Tokyo, Inst Solid State Phys, Chiba 2778581, Japan

[3] Tohoku Univ, Inst Mat Res, Sendai, Miyagi 9808577, Japan

来源：

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN | 2010年 / 79卷 / 08期

关键词：

superconducting ferromagnet; unconventional superconductivity; U-based heavy fermion; UCoGe; magnetization; spontaneous vortex state; MAGNETIC SUPERCONDUCTORS; COEXISTENCE;

D O I：

10.1143/JPSJ.79.083708

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We report ac magnetic susceptibility and dc magnetization measurements on the superconducting ferromagnet UCoGe (with superconducting and Curie temperatures of T-SC similar to 0.5K and T-Curie similar to 2.5 K, respectively). In the normal, ferromagnetic state (T-SC < T < T-Curie), the magnetization curve exhibits a hysteresis loop similar to that of a regular itinerant ferromagnet. Upon lowering the temperature below TSC, the spontaneous magnetization is unchanged, but the hysteresis is markedly enhanced. Even deeply inside the superconducting state, ferromagnetism is not completely shielded, and there is no Meissner region, a magnetic field region of H < H-c1 (a lower critical field). From these results, we suggest that UCoGe is the first material in which ferromagnetism robustly survives in the superconducting state and a spontaneous vortex state without the Meissner state is realized.

引用

页数：4

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