Studying the effect of Zn-substitution on the magnetic and hyperthermic properties of cobalt ferrite nanoparticles

Abstract

The possibility to finely control nanostructured cubic ferrites (M(II)Fe2O4) paves the way to design materials with the desired magnetic properties for specific applications. However, the strict and complex interrelation among the chemical composition, size, polydispersity, shape and surface coating renders their correlation with the magnetic properties not trivial to predict. In this context, this work aims to discuss the magnetic properties and the heating abilities of Zn-substituted cobalt ferrite nanoparticles with different zinc contents (ZnxCo1-xFe2O4 with 0 < x < 0.6), specifically prepared with similar particle sizes (∼7 nm) and size distributions having the crystallite size (∼6 nm) and capping agent amount of 15%. All samples have high saturation magnetisation (Ms) values at 5 K (>100 emu g(-1)). The increase in the zinc content up to x = 0.46 in the structure has resulted in an increase of the saturation magnetisation (Ms) at 5 K. High Ms values have also been revealed at room temperature (∼90 emu g(-1)) for both CoFe2O4 and Zn0.30Co0.70Fe2O4 samples and their heating ability has been tested. Despite a similar saturation magnetisation, the specific absorption rate value for the cobalt ferrite is three times higher than the Zn-substituted one. DC magnetometry results were not sufficient to justify these data, the experimental conditions of SAR and static measurements being quite different. The synergic combination of DC with AC magnetometry and (57)Fe Mössbauer spectroscopy represents a powerful tool to get new insights into the design of suitable heat mediators for magnetic fluid hyperthermia.

Activity Tuning of Cobalt Ferrite Nanoparticles Anchored on N‐Doped Reduced Graphene Oxide as a Potential Oxygen Reduction Electrocatalyst by Zn Substitution in the Spinel Matrix

“…The present work, therefore, is a focused attempt to understand how the overpotential for ORR can be tuned by manipulating the extent of inversion of CoFe 2 O 4 through Zn substitution. Here, we have synthesized Zn substituted cobalt ferrite with the compositional variation represented as CoFe 2‐x Zn x O 4 (x= 0–0.3), following a solvothermal synthesis procedure ,. The composition corresponding to x=0.3 displayed high ORR activity in terms of the onset and half‐wave potentials (E 1/2 ).…”

Physiological Remediation of Cobalt Ferrite Nanoparticles by Ferritin

“…Cobalt ferrite NPs (CoIONPs) arise interest for theranostic applications, data storage, catalysis, environmental and biodevices as their magnetocristalline anisotropy can be finely tuned by cobalt substitution. This approach is particularly useful for magnetic hyperthermia, which benefits from optimized hyperthermic efficacy at tunable excitation with different magnetic field frequencies1617181920. However little is known about the in vivo fate of nanoparticles metallic dopants such as cobalt.…”

Exploring Reaction Conditions to Improve the Magnetic Response of Cobalt-Doped Ferrite Nanoparticles

“…In the interval between 300 °C and 400 °C decomposition of the weakly attached surface functional coating or capping molecules (oleic acid molecules and oleylamine) occurs, as boiling temperatures of oleic acid (OA) and oleylamine (OLA) are 360 °C and 364 °C, respectively. The mass loss of about 20% above 600 °C can be attached to the decomposition of tightly-linked molecules or intermediate carbonates, together with a process of evolution of the ferrite inorganic core [26,27]. To confirm this fact, the residue obtained at TGA has been characterized by XRD (Supplementary Information, Figure S1) and in the diffraction pattern, together with the presence of the Fe 3 O 4 phase, there is a significant concentration of FeO (JCPDS 75-155) and CoFe (JCPDS 44-1433), which is in good accord with the evolution of the inorganic Co x Fe 3− x O 4 core into reduced phases.…”