2026/08/01 by Chao-Chun Wei, Xiaojuan Ni, Sophia Adams +5
Physics and Astronomy · #cond-mat.mtrl-sci
arxiv created 2026/08/01 · arxiv updated 2026/08/04
Non-relativistic spin-splitting (NRSS) antiferromagnets have recently emerged as an important class of magnetic materials that combine compensated magnetism with momentum-dependent spin splitting, offering new opportunities for spintronic applications. Here, we investigate a NiAs-type Fe1+δSb series (δ= 0.17-0.30) using neutron diffraction, pair distribution function, magnetometry and density functional theory calculations. Neutron diffraction establishes that Fe1+δSb adopts a 120^∘ coplanar compensated magnetic order with a non-zero propagation vector k=(1/3, 1/3, 0). Increasing interstitial Fe suppresses the ordered magnetic moment while inducing local symmetry lowering, as revealed by pair distribution function refinements. Density functional theory predicts momentum-dependent spin splitting, dominated by an out-of-plane spin polarization with an odd-parity f-wave-like symmetry, establishing the material as a non-collinear NRSS antiferromagnet. Motivated by the structural similarities between Fe1+δSb and a known altermagnet CrSb, we further investigate their solid solution and find that Cr substitution at intermediate concentrations gives rise to a ferromagnetic component and a cluster spin-glass behavior. These results establish Fe1+δSb as a new platform for non-collinear NRSS antiferromagnetism and demonstrate metal interstitial and substitution as effective parameters for tuning the magnetic order and properties.