We performed 17O nuclear magnetic resonance measurements on superconducting (SC) Sr2RuO4 under in-plane magnetic fields. We found that no new signal appears in the SC state and that the 17O Knight shifts obtained from the double-site measurements remain constant across the first-order phase-transition line, as well as across the second-order phase-transition line as already reported. The present results indicate that the SC spin susceptibility does not decrease in the high-field region, although a magnetization jump in the SC state was reported at low temperatures. Because the spin susceptibility is unchanged in the SC state in Sr2RuO4, we suggest that the first-order phase transition across the upper critical field should be interpreted as a depairing mechanism other than the conventional Pauli-paramagnetic effect.
@article{arxiv.1611.01620,
title = {Absence of $^{17}$O Knight-Shift Changes across the First-Order Phase Transition Line in Sr$_2$RuO$_4$},
author = {Masahiro Manago and Kenji Ishida and Zhiqiang Mao and Yoshiteru Maeno},
journal= {arXiv preprint arXiv:1611.01620},
year = {2016}
}
Comments
5 pages, 3 figures; to appear in Physical Review B Rapid Communications