We report a novel phenomenon intimately related to the spin-triplet superconductivity. It is well known that the spin susceptibility decreases below the superconducting transition temperature in almost all superconductors because of spin-singlet pair formation, while it may remain unchanged in a handful of spin-triplet exceptions. Here we report the observation in Sr2RuO4 with nuclear magnetic resonance (NMR) that the spin susceptibility originating from the Ru-4d electron slightly increases by ∼2\% of total and becomes inhomogeneous in the superconducting state. These are reasonably explained if the electron pairs form the equal-spin-pairing (ESP) in the mixed state. A similar phenomenon was predicted for superfluid 3He forty years ago, but had never been demonstrated in any superconductor.
@article{arxiv.1508.06421,
title = {Spin Polarization Enhanced by Spin-Triplet Pairing in Sr$_2$RuO$_4$ Probed by NMR},
author = {K. Ishida and M. Manago and T. Yamanaka and H. Fukazawa and Z. Q. Mao and Y. Maeno and K. Miyake},
journal= {arXiv preprint arXiv:1508.06421},
year = {2015}
}
Comments
5 pages, 3 figures + supplemental material. To appear in Phys. Rev. B, Rapid Communication