In situ synthesis of lithium ferrite nanoparticle/polymer hybrid
- PDF / 435,935 Bytes
- 8 Pages / 585 x 783 pts Page_size
- 48 Downloads / 197 Views
Lithium ferrite particle/organic hybrid was synthesized in situ from iron–organic and lithium–organic compounds below 100 °C. Spinel ferrite particle/organic hybrid was synthesized by hydrolyzing a mixture of iron (III) 3-allylacetylacetonate (IAA) and lithium acrylate (LA). X-ray diffraction analysis revealed that the crystallinity of spinel particle was dependent on the polymerization treatment and the hydrolysis conditions. The saturation magnetization of hybrid increased with increasing methylhydrazine and water amount of hydrolysis. Nanocrystalline lithium ferrite particle about 5 nm was dispersed in the organic matrix. The hybrid showed neither remanence nor coercive force at room temperature. The magnetization versus field/temperature H/T curves from 100 to 300 K were superimposed on the same curve and satisfied the Langevin equation. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization curve revealed that the blocking temperature was about 75 K. The remanent magnetization and coercive field of the hybrid were 8.9 A·m2/kg and 26.3 kA/m, respectively, at 10 K.
I. INTRODUCTION
Inorganic/organic hybrid materials attract special attentions because of their novel properties derived from combination effects between inorganic and organic phases.1 Inorganic particle/organic hybrid is one of the hybrid materials and consists of nanoparticles and organic matrix. In situ synthesized inorganic particle/ organic hybrid materials have a chemical bond between the inorganic and organic phases and have malleability and flexibility derived from organics. The size of inorganic particle is controlled through the selection of chemical bonds at the nanometer level. The in situ synthesized inorganic particle/organic hybrid materials have the advantage of uniform dispersion of particles when inorganic phase is a magnetic particle, because the agglomeration of particles by magnetic moment and van der Waals force is prevented by organic matrixes. Magnetic particle/organic hybrid is expected for applications in ferrofluid,2 hyperthermia,3 magnetic resonance imaging,4 and materials exhibiting both magnetic properties and processibility of organics. Nanocrystalline magnetic particles below critical size exhibit unique magnetic properties, such as single domain behavior and superparamagnetism,5 which are not observed for the bulk material. a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2007.0113 974
J. Mater. Res., Vol. 22, No. 4, Apr 2007 http://journals.cambridge.org Downloaded: 28 May 2014
Lithium ferrite, Li0.5Fe2.5O4 or LiFe5O8, is an inverse spinel-type ferrite with a high Curie temperature and high saturation magnetization. Because of its superior magnetic properties and low-cost, Li0.5Fe2.5O4 is used in the field of magnetic microwave devices and memory core application.6 Spinel-type lithium ferrite has been confirmed to exist in two different crystalline forms: the ordered and disordered phases. The Li and Fe ions in the octahedral sites are distributed in an ordere
Data Loading...
