Sharp magnetization jump at the first-order superconducting transition in Sr2RuO4

Abstract

The magnetization and magnetic torque of a high-quality single crystal of Sr${}_2$RuO${}_4$ have been measured down to 0.1 K under a precise control of the magnetic-field orientation. When the magnetic field is applied exactly parallel to the $ab$ plane, a sharp magnetization jump $4\pi \delta M$ of $(0.74\pm 0.15)$ G at the upper critical field $H_{c2,ab}\sim 15$ 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 $ab$ plane confirms an intrinsic anisotropy $\Gamma ={\xi }_a/{\xi }_c$ of as large as 60 even at 100 mK, in contrast with the observed $H_{c2}$ anisotropy of $\sim 20$. 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 Sr${}_2$RuO${}_4$.

5 pages, 4 figures (main text) + 2 pages, 2 figures (supplemental material), published in Phys. Rev. B

References in corpus (5)

• Fulde-Ferrell-Larkin-Ovchinnikov State in Heavy Fermion Superconductors
• First-Order Superconducting Transition of Sr2RuO4
• Specific-heat evidence of the first-order superconducting transition in Sr2RuO4
• Theory of Pairing Assisted Spin Polarization in Spin-Triplet Equal Spin Pairing: Origin of Extra Magnetization in Sr_2RuO_4 in Superconducting State
• Anomalous Field-Angle Dependence of the Specific Heat of Heavy-Fermion Superconductor UPt3

Cited by in corpus (6)

• Little-Parks oscillations with half-quantum fluxoid features in Sr2RuO4 micro rings
• Pauli-paramagnetic effects on mixed state properties in a strongly anisotropic superconductor ---Application to Sr_2_RuO_4_---
• Wing structure in the phase diagram of the Ising Ferromagnet URhGe close to its tricritical point investigated by angle-resolved magnetization measurements
• Anisotropy and multiband superconductivity in Sr2RuO4
• Absence of ${}^{17}$O Knight-Shift Changes across the First-Order Phase Transition Line in Sr${}_2$RuO${}_4$
• Quenched metastable vortex states in Sr2RuO4