In situ synthesis of nickel ferrite nanoparticle/organic hybrid
- PDF / 710,236 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 46 Downloads / 189 Views
A NiFe2O4 particle/organic hybrid was synthesized in situ from iron-organic and nickel organic compounds below 100 °C. A mixture of nickel (II) acetylacetonate (NA) and iron (III) 3-allylacetylacetonate (IAA) was hydrolyzed and polymerized yielding spinel oxide particle/oligomer hybrid. X-ray diffraction analysis revealed that the crystallinity of spinel particles was dependent upon the hydrolysis conditions of NA-IAA. Nanocrystalline nickel ferrite particles around 10 nm were uniformly dispersed in the organic matrix. The formation of nickel ferrite was confirmed by energy-dispersive x-ray and x-ray photoelectron spectroscopy. The saturation magnetization of hybrid increased with increasing water amount for hydrolysis. Nano-sized nickel ferrite particle/organic hybrid showed a BH curve with no remanence above 75 K. The magnetization versus H/T curves at 300, 200, and 75 K were superimposed on the same curve and satisfied the Langevin equation. The remanent magnetization and coercive field of the hybrid were 7.4 emu/g and 460 Oe, respectively, at 5 K.
I. INTRODUCTION
Inorganic particle/organic hybrid material consists of composite structures between inorganic and organic phase. Inorganic particulates are chemically bonded to the organic matrix at the nanometer level in the inorganic particle/organic hybrid.1 Magnetic particle/organic composites have attracted attention because of their application in recording media,2 printing agent, ferrofluid,3 magnetic resonance imaging,4 thermomagnetic surgery.5 Nanocrystalline magnetic particles show the size effects, such as superparamagnetism3 and quantum confinement effect.6 Nickel ferrite is inverse spinel, and one of the typical soft magnetic materials, and attracts special attentions because of applications in microwave devices.7 Nickel and related soft ferrite nanoparticles have been synthesized using chemical solution processes, such as coprecipitation,8,9 sol-gel,10 and hydrothermal method.11,12 Iron and nickel salts, such as chloride and nitrate, are hydrolyzed under alkaline conditions in solution yielding iron nickel oxide particles. However, the formation of magnetic particles results in the aggregation of particles during process. Also, the hydrolysis of iron salt with sodium hydroxide resulted in the residual sodium in the products. Usually, coprecipitated and sol-gel-derived
a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2005.0210 1590
http://journals.cambridge.org
J. Mater. Res., Vol. 20, No. 6, Jun 2005 Downloaded: 19 Feb 2015
products are heat-treated above 400 °C to increase the crystallinity and magnetization.8–10 The uniform dispersion of size-controlled inorganic particles is a key for the unique properties of inorganic particle/organic hybrid. However, the blending of magnetic particles into a polymer is quite difficult because of particle agglomeration by magnetic moment. The in situ formation of magnetic particles in a polymer matrix is, therefore, one of the most advantageous methods for the synt
Data Loading...
