Spinel Ferrite Nanoparticles: Correlation of Structure and Magnetism

Abstract

This chapter focuses on the relationship between structural and magnetic properties of cubic spinel ferrite MFe 2 O 4 (M = Mg, Mn, Fe, Co, Ni, Cu and Zn) nanoparticles (NPs). First, a brief overview of the preparation methods yielding well-developed NPs is given. Then, key parameters of magnetic NPs representing their structural and magnetic properties are summarized with link to the relevant methods of characterization. Peculiar features of magnetism in real systems of the NPs at atomic, single-particle, and mesoscopic level, respectively, are also discussed. Finally, the significant part of the chapter is devoted to the discussion of the structural and magnetic properties of the NPs in the context of the relevant preparation routes. Future outlooks in the field profiting from tailoring of the NP properties by doping or design of core-shell spinel-only particles are given.

Saturation of Specific Absorption Rate for Soft and Hard Spinel Ferrite Nanoparticles Synthesized by Polyol Process

“…Moreover, at room temperature, both ZFC and FC magnetization curves display magnetization values of 11.4 emu/g and 26.9 emu/g for nickel and manganese ferrites, respectively. These behaviors are typically for an assembly of nanoparticles with non-negligible particle size distribution which manifest strong interparticle interactions at room temperature [37]. This regime is more pronounced for manganese ferrites if one compares their ZFC and FC magnetization curves (Figure 2d) with those of nickel ferrites (Figure 2c).…”

“…As can be seen in Figure 2c,d, the difference between T IRR and T B is 30 K and 70 K for nickel and manganese ferrites, respectively. It has to be noted that for monodispersed and non-interacting single-domain magnetic particles, assumed as ideal superparamagnetic nanoparticles, the T IRR coincides with T B , the peak is narrow and both the ZFC and FC magnetization curves decrease progressively towards zero while their curvature became negative in the vicinity of room temperature [37,38]. The ZFC magnetization curve drops to zero as the temperature decreases below T B .…”

Magnetocrystalline and Surface Anisotropy in CoFe2O4 Nanoparticles

“…According to the Vogel–Fulcher law, weak interparticle interactions are accounted for by a temperature term T 0 [ 29 , 30 , 31 ]: …”

Polyol-Made Spinel Ferrite Nanoparticles—Local Structure and Operating Conditions: NiFe2O4 as a Case Study

“…However, this structure may deviate when nanocrystals are prepared by soft chemistry: the atomic ratio of Co 2+ located in A sites being directly dependent on the operating synthesis conditions (Ammar et al, 2001;Artus et al, 2011). In general, the more they differ from the thermodynamic conditions, the greater the deviation, and conversely, the closer they are, the smaller the deviation (Pacakova et al, 2017). Even rare, the same trends have been observed in nickel ferrite nanoparticles.…”