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arXiv · 1611.01620

Absence of $^{17}$O Knight-Shift Changes across the First-Order Phase Transition Line in Sr$_2$RuO$_4$

Masahiro Manago·Kenji Ishida·Zhiqiang Mao·Yoshiteru Maeno
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Abstract

We performed $^{17}$O nuclear magnetic resonance measurements on superconducting (SC) Sr$_2$RuO$_4$ under in-plane magnetic fields. We found that no new signal appears in the SC state and that the $^{17}$O 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 Sr$_2$RuO$_4$, 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.

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Masahiro Manago, Kenji Ishida, Zhiqiang Mao, Yoshiteru Maeno. 2016-11-05. Absence of $^{17}$O Knight-Shift Changes across the First-Order Phase Transition Line in Sr$_2$RuO$_4$. https://doi.org/10.1103/physrevb.94.180507

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