Magnetic Properties of Bi-Magnetic Core/Shell Nanoparticles: The Case of Thin Shells
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 NiFe<sub>2</sub>O<sub>4</sub> around t...
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| Main Authors: | , , , , , , |
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| Format: | article |
| Language: | EN |
| Published: |
MDPI AG
2021
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| Subjects: | |
| Online Access: | https://doaj.org/article/2700256d8db74311ae897be4b453e1f9 |
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| Summary: | 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 NiFe<sub>2</sub>O<sub>4</sub> around the magnetically hard 8 nm CoFe<sub>2</sub>O<sub>4</sub> core nanoparticle. Magnetization measurements showed an increase in the coercivity of the single-phase CoFe<sub>2</sub>O<sub>4</sub> seed nanoparticles from ~1.2 T to ~1.5 T and to ~2.0 T for CoFe<sub>2</sub>O<sub>4</sub>/NiFe<sub>2</sub>O<sub>4</sub> and CoFe<sub>2</sub>O<sub>4</sub>/NiO, respectively. The NiFe<sub>2</sub>O<sub>4</sub> 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. |
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