Bi-magnetic core/shell nanoparticles were synthesized by a two-step high-temperature decomposition method of metal acetylacetonate salts. Transmission electron microscopy confirmed the formation of an ultrathin shell (~0.6 nm) of NiO and NiFe2O4 around the magnetically hard 8 nm CoFe2O4 core nanoparticle. Magnetization measurements showed an increase in the coercivity of the single-phase CoFe2O4 seed nanoparticles from ~1.2 T to ~1.5 T and to ~2.0 T for CoFe2O4/NiFe2O4 and CoFe2O4/NiO, respectively. The NiFe2O4 shell also increases the magnetic volume of particles and the dipolar interparticle interactions. In contrast, the NiO shell prevents such interactions and keeps the magnetic volume almost unchanged.

Magnetic Properties of Bi-Magnetic Core/Shell Nanoparticles: The Case of Thin Shells

Laureti Sara;Peddis Davide
2021

Abstract

Bi-magnetic core/shell nanoparticles were synthesized by a two-step high-temperature decomposition method of metal acetylacetonate salts. Transmission electron microscopy confirmed the formation of an ultrathin shell (~0.6 nm) of NiO and NiFe2O4 around the magnetically hard 8 nm CoFe2O4 core nanoparticle. Magnetization measurements showed an increase in the coercivity of the single-phase CoFe2O4 seed nanoparticles from ~1.2 T to ~1.5 T and to ~2.0 T for CoFe2O4/NiFe2O4 and CoFe2O4/NiO, respectively. The NiFe2O4 shell also increases the magnetic volume of particles and the dipolar interparticle interactions. In contrast, the NiO shell prevents such interactions and keeps the magnetic volume almost unchanged.
2021
Istituto di Struttura della Materia - ISM - Sede Roma Tor Vergata
magnetic nanoparticles
exchange-coupling
magnetic volume
CoFe2O4
NiFe2O4
NiO
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/460262
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