Suppression of ferromagnetic spin correlation in the filled skutterudite superconductor SrOs₄As₁₂ revealed by ⁷⁵As NQR-NMR

Recently new filled-skutterudite compounds SrT₄As₁₂ (T = Fe, Ru, Os) have been synthesized, which provides a new opportunity of systematic studies of the effects of different d electron of 3d, 4d and 5d in the systems [1]. Motivated by the recent observation of ferromagnetic spin correlations in the 3d compound SrFe₄As₁₂ [2], we have carried out nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) measurements to investigate the role of magnetic fluctuations in the newly discovered superconductor 5d-compound SrOs₄As₁₂ which exhibits a superconducting transition at T_c = 4.8 K [3]. From the temperature dependence of Knight shift K and nuclear spin lattice relaxation time T₁, we found that no obvious ferromagnetic spin correlations in SrOs₄As₁₂. Furthermore, the temperature dependence of 1/T₁ in the superconducting state evidences a conventional s-wave superconductivity in SrOs₄As₁₂.

[1] K. Nishine, Y. Kawamura, J. Hayashi, and C. Sekine, Jpn. J.Appl. Phys. 56, 05FB01 (2017).
[2] Q.-P, Ding, et al. Phys. Rev. B 98, 155149 (2018).
[3] Q.-P. Ding et al., Phys. Rev. B 100, 054516 (2019).