Structure and cationic distribution dependent soft magnetic properties of single-domain Mg1−Ni Fe2O4 (0 ≤ x ≤ 1.0) nanocrystals

The effects of Ni$^{2+}$ substitution on the structure (lattice parameters, cations distribution, average radii, cation-cation/anion bond lengths and angles) soft magnetic properties Mg$_{1-x}$Ni$_x$Fe$_2$O$_4$ ($0 \le x 1.0$) nanocrystals have been studied by x-ray diffraction with Rietveld refinement, transmittance electron microscopy, Mossbauer spectroscopy magnetization measurements. mostly inverse spinel was found in MgFe$_2$O$_4$ nanoparticles inversion factor is further increased Ni-substitution up to a complete NiFe$_2$O$_4$. synthesized ferrites small particle size (20 - 30 nm) exhibit single-domain behavior critical domain about 40 nm. An observed monotonic increase drastic decrease coercivity at 5 K result lowest anisotropy constant Ku (2.8 kJ/m3) for = 0.5. We discuss evolution correlation subsequent cations-redistribution between sites two sublattices corresponding structural changes inter-ionic distances.