Magnetic properties of nanosized iron oxide particles precipitated in alginate hydrogels

Abstract

Articles you may be interested inDistinguishing magnetic particle size of iron oxide nanoparticles with first-order reversal curves Effect of size, composition, and morphology on magnetic performance: First-order reversal curves evaluation of iron oxide nanoparticles J. Appl. Phys. 115, 044314 (2014); 10.1063/1.4863543Role of inhomogeneous cation distribution in magnetic enhancement of nanosized Ni0.35Zn0.65Fe2O4: A structural, magnetic, and hyperfine study Synthesis and magnetic properties of gold coated iron oxide nanoparticles Nanoparticles of ␥-Fe 2 O 3 ͑size 2 -3 nm͒ were precipitated in alginate hydrogels by cross-linking sodium alginate with Fe ions in a methanol-water solution. The zero-field-cooled and field-cooled magnetization measurements between 5 and 350 K and the hysteresis in the M vs H relation below the blocking temperature indicate superparamagnetic behavior. The temperature dependence of the coercive field is not consistent with the T 1/2 behavior predicted by Néel and Brown for the noninteracting particles. The average diameter of the nanoparticles determined from the magnetic data is consistently larger than the corresponding particle size determined by x-ray diffraction, perhaps due to interparticle magnetic interactions.

Magnetic relaxation and dissipative heating in ferrofluids

“…Electronic mail: glawes@wayne.edu ␥-Fe 2 O 3 nanoparticles in alginate hydrogel ͑sample AGFO͒ using the method outlined in Ref. 25. This method produces small ␥-Fe 2 O 3 magnetic crystallites embedded inside a larger alginate nanoparticles, as can be seen in the transmission electron microscope ͑TEM͒ image in Fig.…”

Biofunctional Composites of Polysaccharides Containing Inorganic Nanoparticles

“…This is an important outcome since maghemite, the product that results in this case from the oxidation of magnetite, has lower saturation magnetization than magnetite. Magnetic iron oxide nanoparticles have been also synthesized in the presence of other polysaccharides such as starch (D. K. Kim et al, 2003), alginate (Morales et al, 2008;Naik et al, 2005), dextran (Dou et al, 2008) and chitosan (Hernandez et al, 2009), using the coprecipitation method. The presence of starch molecules limited the size of the Fe 3 O 4 nanoparticles to 6 nm and the agglomeration of the coated nanoparticles was controlled upon the cleavage of the glycosidic bonds of the polymer, which allowed preparing magnetic composite particles with average size smaller than commercially available dextran-coated magnetic nanoparticles.…”

Nonlinear energy dissipation of magnetic nanoparticles in oscillating magnetic fields

“…As such, Rosensweig In this contribution we approach this problem from an alternative point of view by solving the phenomenological magnetization relaxation equation of Shliomis [26] exactly for the case of arbitrary magnetic field amplitude and frequency and by solving the magnetization relaxation equation of Martsenyuk, Raikher, and Shliomis (MRSh) [28] numerically. The latter has been found to accurately describe the magnetic field and shear rate dependence of the socalled magnetoviscosity of dilute ferrofluids [29][30][31]. Rotational Brownian dynamics simulations of non-interacting particles subjected to an oscillating magnetic field are compared with these solutions of the phenomenological models.…”