Effects of intrinsic and extrinsic multi-phased lattice structure and chemical heterogeneity on the control of ferrimagnetic properties in Co rich spinel ferrite

The present work reports the structural and magnetic properties in spinel ferrite composition around Co2.25Fe0.75O4 as the function of self-composite structure (ratio of two spinel phase components), coexisting impurity phase of hematite, and non-stoichiometric chemical composition. The neutron diffraction patterns have been used to determine lattice structure and magnetic moment. The neutron depolarization experiments have indicated spin reorientation at lower temperature for the single phased sample. The magnetization measurements confirmed the blocking of magnetic domains, possible magnetic spin compensation and magnetic exchange bias effect. The sample coexisting with small hematite phase has shown the maximum coercivity (-14.682 kOe), remanent magnetization (-1.4657 mu B) and saturation magnetization (-2.027 mu B) with small exchange bias shift (-71 Oe) at 5 K. The single phased sample exhibited the lowest magnetic moment (-0.3775 mu B) with maximum exchange bias shift (-543 Oe) and the highest cooling-field induced enhancement of coercivity (3691 Oe). The experiments confirmed a large scope of tuning the ferrimagnetic parameters by controlling the phase fraction and interfacial phases in Co rich spinel ferrite.