Sharp magnetization jump at the first-order superconducting transition in Sr2RuO4
Abstract
The magnetization and magnetic torque of a high-quality single crystal of Sr2RuO4 have been measured down to 0.1 K under precise control of the magnetic-field orientation. When the magnetic field is applied exactly parallel to the a b plane, a sharp magnetization jump 4 π δ M of (0.74 ±0.15 ) G at the upper critical field Hc 2 ,a b∼15 kOe with a field hysteresis of 100 Oe is observed at low temperatures, evidencing a first-order superconducting-normal transition. A strong magnetic torque appearing when H is slightly tilted away from the a b plane confirms an intrinsic anisotropy Γ =ξa/ξc of as large as 60 even at 100 mK, in contrast with the observed Hc 2 anisotropy of ∼20 . The present results raise fundamental issues in both the existing spin-triplet and spin-singlet scenarios, providing, in turn, crucial hints toward the resolution of the superconducting nature of Sr2RuO4 .
- Publication:
-
Physical Review B
- Pub Date:
- December 2014
- DOI:
- 10.1103/PhysRevB.90.220502
- arXiv:
- arXiv:1410.0798
- Bibcode:
- 2014PhRvB..90v0502K
- Keywords:
-
- 74.70.Pq;
- 74.25.Bt;
- 74.25.Dw;
- Ruthenates;
- Thermodynamic properties;
- Superconductivity phase diagrams;
- Condensed Matter - Superconductivity;
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- 5 pages, 4 figures (main text) + 2 pages, 2 figures (supplemental material), published in Phys. Rev. B