# Reduction of the spin susceptibility in the superconducting state of Sr2RuO4 observed by polarized neutron scattering

A. N. Petsch, M. Zhu, Mechthild Enderle, Z. Q. Mao, Y. Maeno, I. I. Mazin, S. M. Hayden

Research output: Contribution to journalArticle (Academic Journal)

## Abstract

Recent observations [A.~Pustogow et al. Nature 574, 72 (2019)] of a drop of the $^{17}$O nuclear magnetic resonance (NMR) Knight shift in the superconducting state of Sr$_2$RuO$_4$ challenged the popular picture of a chiral odd-parity paired state in this compound. Here we use polarized neutron scattering to show that there is a $34 \pm 6$ % drop in the magnetic susceptibility at the ruthenium site below the superconducting transition temperature. Measurements are made at lower fields $H \sim \tfrac{1}{3} H_{c2}$ than a previous study allowing the suppression to be observed. Our results are consistent with the recent NMR observations and rule out the chiral odd-parity $\mathbf{d}=\hat{\mathbf{z}}(k_x\pm ik_y)$ state. The observed susceptibility is consistent with several recent proposals including even-parity $B_{1g}$ and odd-parity helical states.
Original language English Physical Review Letters Accepted/In press - 7 Feb 2020

### Bibliographical note

New version with Supplementary Material discussing orbital contributions to the susceptibility, Fermi liquid corrections and a two fluid model

## Keywords

• cond-mat.supr-con
• cond-mat.str-el