Antiferromagnetic order and Fermi liquid behavior in uniaxially stressed Sr₂RuO₄investigated by ¹⁷O NMR

Uniaxially stressed Sr₂RuO₄ has been shown to exhibit a factor 2.5 increase in the superconducting T_c, resulting from the passage of the Fermi energy through a van Hove singularity [1]. Further stress reduces T_c, with recent μSR measurements giving evidence for a magnetic phase stabilizing at 1.05 GPa [2]. Presented here are the results of ¹⁷O NMR spectroscopy and relaxation measurements in and around this high stress magnetic phase. Relaxation rates and spectral broadening characterize a phase boundary consistent with the proposed line of transitions. Differences in the spectral broadening and relaxation rates measured at separate ¹⁷O sites are consistent with an in-plane magnetic wavevector (q_a,q_b) different from the (0.3,0.3) incommensurate fluctuations observed at zero stress [3]. At 1.6 GPa, beyond the magnetic phase, relaxation rates again follow standard Fermi liquid behavior, with (1/T₁T) measuring similar to reports for the unstressed material.



[1] Steppke, A. et al. Science 355, eaaf9398 (2017).

[2] Grinenko, V., Ghosh, S., Sarkar, R. et al. Nat. Phys. 17, 748–754 (2021).

[3] Steffens, P. et al. Phys. Rev. Lett. 122, 047004 (2019).