The effect of temperature on the structure and magnetic properties of Co0.5Ni0.5Fe2O4 spinel nanoferrite

Exchange bias and surface effects in bimagneticCoO−core/Co0.5Ni0.5Fe2O4Lavorato1, Winkler2, Ghirri3 et al. 2016Phys. Rev. B232140View full textAdd to dashboardCite

“…The most noticeable one is the enhancement of the coercive field when the sample is annealed: at 10 K, H C ∼ 5.5 kOe and ∼14.6 kOe for and annealed nanoparticles, respectively. The enhancement of H C in the annealed sample is even more evident when it is compared with Co 0.5 Ni 0.5 Fe 2 O 4 single-phase nanoparticles, whose H C is, for example, ∼6 and ∼12 kOe for 7.6-and 22-nm nanoparticles [46,47], respectively. While the coercivity of annealed nanoparticles increases monotonically as the temperature is decreased, H C diminishes below 14 K for as-synthesized nanoparticles, as shown in Fig.…”

Investigating the Role of Shell Thickness and Field Cooling on Saturation Magnetization and Its Temperature Dependence in Fe3O4/γ-Fe2O3 Core/Shell Nanoparticles

“…The deviation from the original Bloch's law could be attributed to the surface and interface effects [49][50][51][52]. Due to the broken exchange bonds [53] at the core/shell interface, the interface spins are suggested to be in disordered states. We suggest that (as shown in [37]) at the core/shell interface, spin-glass like structures [49,50] occur with amounts that increase with shell thickness.…”

Sol–Gel Route for the Synthesis of CoFe2–xErxO4 Nanocrystalline Ferrites and the Investigation of Structural and Magnetic Properties for Magnetic Device Applications

“…More explicitly, the magnetic properties of ferrites truly depend on the particle size, cation distributions, A–B interactions, and doping elements. , The increase of saturation magnetization reported with nonmagnetic Zn doping in the CoFe 2 O 4 matrix is due to the switching of Fe 3+ ions to the octahedral B-sites from tetrahedral A-sites . Besides, Abdallah et al reported that the modification of crystallite size and preference of Fe 3+ ions at octahedral sites is responsible for the increase in saturation magnetization. In the present case, as the Er 3+ ions have preference to hold the octahedral site because of their larger ionic radius as compared to the Fe 3+ ; therefore, the Co 2+ ions may partially transfer to the tetrahedral site by moving the same amount of Fe 3+ ions from tetrahedral to octahedral sites .…”