Synthesis and characterization of Gd-doped magnetite nanoparticles

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:423

Article

Zhang, Honghu^1,2  Malik, Vikash¹  Mallapragada, Surya^1,3  Akinc, Mufit^1,2 

[1] Ames Lab, S Dept Energy, Ames, IA 50011 USA

[2] Iowa State Univ, Dept Mat Sci Engn, Ames, IA 50011 USA

[3] Iowa State Univ, Dept Chem & Biol Engn, Ames, IA 50011 USA

关键词: Magnetite nanoparticles;    Aqueous synthesis;    Rare earth;    Doping;    Crystal size;   

DOI  :  10.1016/j.jmmm.2016.10.005

来源: Elsevier

【 摘 要 】

Synthesis of magnetite nanoparticles has attracted increasing interest due to their importance in biomedical and technological applications. Tunable magnetic properties of magnetite nanoparticles to meet specific requirements will greatly expand the spectrum of applications. Tremendous efforts have been devoted to studying and controlling the size, shape and magnetic properties of magnetite nanoparticles. Here we investigate gadolinium (Gd) doping to influence the growth process as well as magnetic properties of magnetite nanocrystals via a simple co-precipitation method under mild conditions in aqueous media. Gd doping was found to affect the growth process leading to synthesis of controllable particle sizes under the conditions tested (0-10 at% Gd3+). Typically, undoped and 5 at% Gd-doped magnetite nanoparticles were found to have crystal sizes of about 18 and 44 nm, respectively, supported by X-ray diffraction and transmission electron microscopy. Our results showed that Gd-doped nanoparticles retained the magnetite crystal structure, with Gd3+ randomly incorporated in the crystal lattice, probably in the octahedral sites. The composition of 5 at% Gd-doped magnetite was Fe(3-x)GdxO4 (x=0.085 +/- 0.002), as determined by inductively coupled plasma mass spectrometry. 5 at% Gd-doped nanoparticles exhibited ferrimagnetic properties with small coercivity (similar to 65 Oe) and slightly decreased magnetization at 260 K in contrast to the undoped, superparamagnetic magnetite nanoparticles. Templation by the bacterial biomineralization protein Mms6 did not appear to affect the growth of the Gd-doped magnetite particles synthesized by this method.

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