Hole Doping and Antiferromagnetic Correlations above the N{é}el temperature of the Topological Semimetal (Sr$_{1-x}$K$_x$)MnSb$_2$

Abstract

Neutron diffraction and magnetic susceptibility studies of orthorhombic single crystal (Sr0.97K0.03)MnSb2 confirm the three dimensional (3D) C-type antiferromagnetic (AFM) ordering of the Mn 2+ moments at TN = 305 ± 3 K which is slightly higher than that of the parent SrMnSb2 with TN = 297 ± 3 K. Susceptibility measurements of the K-doped and parent crystals above TN are characteristic of 2D AFM systems. This is consistent with high temperature neutron diffraction of the parent compound that display persisting 2D AFM correlations well above TN to at least ∼ 560 K with no evidence of a ferromagnetic phase. Analysis of the de Haas van Alphen magnetic oscillations of the K-doped crystal is consistent with hole doping.