Superparamagnetic MFe2O4 (M = Fe, Co, Mn) Nanoparticles: Tuning the Particle Size and Magnetic Properties through a Novel One-Step Coprecipitation Route
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- 作者：Clara Pereira ; Andr茅 M. Pereira ; Carlos Fernandes ; Mariana Rocha ; Ricardo Mendes ; Mar铆a Paz Fern谩ndez-Garc铆a ; Alexandra Guedes ; Pedro B. Tavares ; Jean-Marc Gren猫che ; Jo茫o P. Ara煤jo ; Cristina Freire
- 刊名：Chemistry of Materials
- 出版年：2012
- 出版时间：April 24, 2012
- 年：2012
- 卷：24
- 期：8
- 页码：1496-1504
- 全文大小：536K
- 年卷期：v.24,no.8(April 24, 2012)
- ISSN：1520-5002
文摘
Superparamagnetic ferrite nanoparticles (MFe2O4, where M = Fe, Co, Mn) were synthesized through a novel one-step aqueous coprecipitation method based on the use of a new type of alkaline agent: the alkanolamines isopropanolamine and diisopropanolamine. The role played by the bases on the particles鈥?size, chemical composition, and magnetic properties was investigated and compared directly with the effect of the traditional inorganic base NaOH. The novel MFe2O4 nanomaterials exhibited high colloidal stability, particle sizes in the range of 4鈥?2 nm, and superparamagnetic properties. More remarkably, they presented smaller particle sizes (up to 6 times) and enhanced saturation magnetization (up to 1.3 times) relative to those prepared with NaOH. Furthermore, the nanomaterials exhibited improved magnetic properties when compared with nanoferrites of similar size synthesized by coprecipitation with other bases or by other methods reported in the literature. The alkanolamines were responsible for these achievements by acting both as alkaline agents and as complexing agents that controlled the particle size during the synthesis process and improved the spin rearrangement at the surface (thinner magnetic 鈥渄ead鈥?layers). These results open new horizons for the design of water-dispersible MFe2O4 nanoparticles with tuned properties through a versatile and easily scalable coprecipitation route.