Self-Limitations of Heat Release in Coupled Core-Shell Spinel Ferrite Nanoparticles: Frequency, Time, and Temperature Dependencies

Abstract

We explored a series of highly uniform magnetic nanoparticles (MNPs) with a core-shell nanoarchitecture prepared by an efficient solvothermal approach. In our study, we focused on the water dispersion of MNPs based on two different CoFe2O4 core sizes and the chemical nature of the shell (MnFe2O4 and spinel iron oxide). We performed an uncommon systematic investigation of the time and temperature evolution of the adiabatic heat release at different frequencies of the alternating magnetic field (AMF). Our systematic study elucidates the nontrivial variations in the heating efficiency of core-shell MNPs concerning their structural, magnetic, and morphological properties. In addition, we identified anomalies in the temperature and frequency dependencies of the specific power absorption (SPA). We conclude that after the initial heating phase, the heat release is governed by the competition of the Brown and Néel mechanism. In addition, we demonstrated that a rational parameter sufficiently mirroring the heating ability is the mean magnetic moment per MNP. Our study, thus, paves the road to fine control of the AMF-induced heating by MNPs with fine-tuned structural, chemical, and magnetic parameters. Importantly, we claim that the nontrivial variations of the SPA with the temperature must be considered, e.g., in the emerging concept of MF-assisted catalysis, where the temperature profile influences the undergoing chemical reactions.

Manganese Ferrite–Hydroxyapatite Nanocomposite Synthesis: Biogenic Waste Remodeling for Water Decontamination

“…In this regard, nano-sized magnetic particles overcome these glitches and can yield bigger specific surface areas, which produce superior adsorption or photocatalytic capacities for the elimination of contamination [ 19 , 20 ]. Nanotextured ferrite is a type of composite oxide with the key constituents of trivalent iron oxides [ 21 ]. These benevolent materials have triggered eclectic public concern due to superior physical and chemical features, viz.…”

Hard–Soft Core–Shell Architecture Formation from Cubic Cobalt Ferrite Nanoparticles

“…Recently, we set up a versatile solvothermal synthesis method able to produce single-phase spherical particles [ 70 , 71 ], chemically mixed spinel phases [ 72 , 73 ], homogeneous spherical bi-magnetic core–shell NPs [ 46 , 70 , 74 , 75 ], and flower-like Ag-spinel ferrite nanoarchitectures [ 1 ] with high crystallinity, low size dispersity, and precise control of the shell growth.…”

On the thermal and hydrothermal stability of spinel iron oxide nanoparticles as single and core-shell hard-soft phases

“…and humidity (e.g., aqueous colloidal dispersion), conditions that very often are present for some specific application. [13][14][15][16][17] Moreover, the transition in nanosized systems is size-dependent. [3,[18][19][20][21][22][23][24][25][26] In the literature, there are several ways to stabilize the spinel iron oxides from phase transition.…”