Recent observations [A. Pustogow, Nature (London) 574, 72 (2019).NATUAS0028-083610.1038/s41586-019-1596-2] of a drop of the O17 nuclear magnetic resonance (NMR) Knight shift in the superconducting state of Sr2RuO4 challenged the popular picture of a chiral odd-parity paired state in this compound. Here we use polarized neutron scattering (PNS) to show that there is a 34±6% drop in the magnetic susceptibility at the Ru site below the superconducting transition temperature. We measure at lower fields H∼13Hc2 than a previous PNS study allowing the suppression to be observed. The PNS measurements show a smaller susceptibility suppression than NMR measurements performed at similar field and temperature. Our results rule out the chiral odd-parity d=z^(kx±iky) state and are consistent with several recent proposals for the order parameter including even-parity B1g and odd-parity helical states.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)