Upper critical field under hydrostatic pressure in UCoGe

International Conference on Strongly Correlated Electron Systems 2014

Bastien, Gaël^1,2 ; Knebel, Georg^1,2 ; Aoki, Dai^1,2,3 ; Flouquet, Jacques^1,2

University Grenoble Alpes, INAC-SPSMS, Grenoble

F-38000, France^1

CEA, INAC-SPSMS, Grenoble

F-38000, France^2

IMR-Tohoku University, Oarai, Japan^3

关键词: Ferromagnetic phase;    Ferromagnetic superconductors;    Magnetic fluctuation;    Magnetization axis;    Pair-breaking mechanism;    Paramagnetic phase;    Pressure dependence;    Upper critical fields;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/592/1/012068/pdf
DOI  :  10.1088/1742-6596/592/1/012068

来源: IOP

【 摘 要 】

We report on the pressure dependence of the upper superconductivity critical field Hc2of the ferromagnetic superconductor UCoGe for field along the c axis, which is the easy magnetization axis. The surprising result is the upward curvature and strong enhancement of the upper critical field on cooling. This enhancement is even more pronounced above the critical pressure pcin the paramagnetic phase than in the ferromagnetic phase below pc. This effect cannot be explained by models based on the suppression of pair building magnetic fluctuations under magnetic field. That points out either decrease of the pair breaking mechanism under field or fluctuations favorable for the Cooper pairing linked to the wing structure of ferromagnetism near the critical pressure, where ferromagnetism is suppressed.