Single Crystal Growth and Superconductivity in La7Ni3 without Inversion Symmetry in the Crystal Structure

International Conference on Strongly Correlated Electron Systems 2016

Nakamura, Ai^1 ; Honda, Fuminori^1 ; Homma, Yoshiya^1 ; Li, Dexin^1 ; Nishimura, Kengo^2 ; Kakihana, Masashi^2 ; Hedo, Masato^3 ; Nakama, Takao^3 ; O'Nuki, Yoshichika^3 ; Aoki, Dai^1,4

Institute for Materials Research, Tohoku University, Oarai, Ibaraki

311-1313, Japan^1

Graduate School of Engineering and Science, University of the Ryukyus, Nishihara, Okinawa

903-0213, Japan^2

Faculty of Science, University of the Ryukyus, Nishihara, Okinawa

903-0213, Japan^3

INAC/PHELIQS, CEA-Grenoble, Grenoble

38054, France^4

关键词: Bulk superconductivity;    Electronic specific heat;    Electronic specific heat coefficient;    Hexagonal structures;    Inversion symmetry;    Non-centrosymmetric;    Temperature dependence;    Upper critical fields;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/807/5/052012/pdf
DOI  :  10.1088/1742-6596/807/5/052012

来源: IOP

【 摘 要 】

We succeeded in growing single crystals of La7Ni3with the non-centrosymmetric hexagonal structure by the Bridgman method, and measured the electrical resistivity and specific heat under magnetic fields. The superconducting transition temperature Tscis 2.4 K. The electronic specific heat coefficient γ is 44 mJ/(K2-f.u.-mol). Correspondingly, the upper critical field Hc2(0) in superconductivity is large, Hc2= 27 kOe. The electronic specific heat shows the jump at Tsc= 2.4 K, indicating the bulk superconductivity with ΔCe/γTc= 1.2, which is close to the weak coupling BCS value of 1.43. Although the temperature dependence of specific heat and some parameters of superconductivity are well explained by the conventional BCS model, the temperature dependence of Hc2is not consistent with the simple BCS model.