Intrinsic magnetic properties and domain structure of ThMn12-type (Sm, Zr)(Fe, Co, M)12 (M <b>=</b> Ti, Mo) compounds

The structure, intrinsic magnetic properties, and domain structure of Sm0.7Zr0.3(Fe0.75Co0.25)11.5M0.5 (M = Ti, Mo) compounds were systematically investigated using neutron diffraction, magnetic measurements, magneto-optical Kerr effect, and first-principles calculations. The results demonstrate that the ThMn12-type structure is co-stabilized by substituting Zr for Sm at the 2a site and M for Fe at the 8i site. The effect of M substitution on the electronic band structure can be explained by the rigid band model, where the d–d electron-orbital hybridization between M and Fe leads to a negative effect on the Fe local magnetic moment. Besides, M changes the magnetic anisotropy by altering the electronic density surrounding Sm. Both the compounds exhibit higher Curie temperatures and magnetocrystalline anisotropy fields compared to the well-known Nd2Fe14B magnet, with Tc and μ0Ha reaching 819.3 K and 9.23 T for M = Ti, and 820.0 K and 8.41 T for M = Mo, respectively. The relevant magnetic domain parameters also indicate that these compounds have significant potential for the development of permanent magnet materials.