Large enhancements of magnetic anisotropy in oxide-free iron nanoparticles

Monson, Todd C.; Venturini, E. L.; Petkov, Valeri; Ren, Yang; Lavin, Judith Maria; Huber, Dale L.

doi:10.1016/j.jmmm.2012.11.026

Cited by 23 publications

(14 citation statements)

References 18 publications

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“…In order to achieve an efficient MDT, various polymeric/inorganic hybrid materials have been suggested that offer unique properties because of their small size, limited toxicity [ 2 ], low production cost, ease of separation and detection [ 3 ]. The magnetic nanoparticles often tend to form large aggregates owing to the strong magnetic dipole–dipole attractions among particles.…”

Section: Introductionmentioning

confidence: 99%

Investigation of magnetically controlled water intake behavior of Iron Oxide Impregnated Superparamagnetic Casein Nanoparticles (IOICNPs)

Singh

Bajpai

2014

J Nanobiotechnol

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Iron oxide impregnated casein nanoparticles (IOICNPs) were prepared by in-situ precipitation of iron oxide within the casein matrix. The resulting iron oxide impregnated casein nanoparticles (IOICNPs) were characterized by Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), Vibrating sample magnetometer (VSM) and Raman spectroscopy. The FTIR analysis confirmed the impregnation of iron oxide into the casein matrix whereas XPS analysis indicated for complete oxidation of iron (II) to iron(III) as evident from the presence of the observed representative peaks of iron oxide. The nanoparticles were allowed to swell in phosphate buffer saline (PBS) and the influence of factors such as chemical composition of nanoparticles, pH and temperature of the swelling bath, and applied magnetic field was investigated on the water intake capacity of the nanoparticles. The prepared nanoparticles showed potential to function as a nanocarrier for possible applications in magnetically targeted delivery of anticancer drugs.

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Section: Introductionmentioning

confidence: 99%

Investigation of magnetically controlled water intake behavior of Iron Oxide Impregnated Superparamagnetic Casein Nanoparticles (IOICNPs)

Singh

Bajpai

2014

J Nanobiotechnol

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“…The low value of compared to bulk as well as the non-saturation of at 90 kOe are likely due to canting of the magnetic moments in the iron core. Other reported results on iron nanoparticles coated with nonmagnetic material include 4.6 nm Fe cores coated in Pt with ~179 emu/g at 4 K (Pana, et al, 2013) and 5 nm Fe nanoparticles coated with surfactant (βdikeytone) with ~210 at 5 K (Monson, et al, 2013). Thus, the value of likely depends quite strongly on the size of the Fe core.…”

Section: Analysis Of Vs Abovementioning

confidence: 97%

“…Co-Pt (Park & Cheon, 2001), Fe-γ-Fe 2 O 3 , and studies on Fe nanoparticles of various sizes (Kneller & Luborsky, 1963;Monson, et al, 2013;Ibusuki, et al, 2001;Xiao, et al, 1986;.…”

Section: Introductionmentioning

confidence: 99%

Effects of Size and Size Distribution on the Magnetic Properties of Maghemite Nanoparticles and Iron-Platinum Core-Shell Nanoparticles

Pisane¹

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Magnetic nanoparticles with large magnetic moments that can be manipulated with an external magnetic field, have potential uses in medicine because their sizes are comparable to biological scales. For such applications it is important to understand how their magnetic properties are affected by their size and size distribution inherently present in magnetic nanoparticles. For this purpose, maghemite (γ-Fe 2 O 3) nanoparticles with average diameters of 7.0±0.8 nm, 6.3±0.6 nm, 3.4±0.8 nm and 2.5±0.7 nm and Fe-Pt core-shell nanoparticles with an approximate core diameter of 2.2 nm were synthesized and investigated. To aid in the interpretation of the magnetic properties, the structural properties of these nanoparticles were investigated using transmission electron microscopy (TEM), X-ray diffraction (XRD), infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). For investigations of the magnetic properties, detailed ac and dc magnetic characterization is presented and discussed in terms of a distribution of particle sizes and magnetic moments. The dc magnetization measurements cover the temperature range from 2 K to 350 K and magnetic fields up to 90 kOe. The temperature dependence of the ac susceptibilities, χ′ and χ″, was measured at various frequencies from 10 Hz to 5 kHz. From the zero field-cooled dc magnetization, the values of blocking temperature have been determined and the ac magnetic data was used to determine the contribution of interparticle interactions to the observed blocking temperature for different sized nanoparticles. The measured blocking temperatures of the maghemite nanoparticles are =35 K, 42 K, 21 K, and 29 K with contributions from interparticle interactions given in terms of =0 K, 11 K, 2.5 K, and 12.5 K for the 7.0 nm, 6.3 nm, 3.4 nm, and 2.5 nm samples respectively. From the variation of with ac measurement frequency, the anisotropy constants determined for the maghemite nanoparticles are: =5.57, 7.51, 18.57, and 79.9 in units of 10 5 erg/cm 3 for the 7.0 nm, 6.3 nm, 3.4 nm, and 2.5 nm samples with a Néel-Brown attempt frequency of =2.6×10 10 Hz. The same approach applied to Fe-Pt nanoparticles yields =13 K, =5 K, =4.74×10 6 erg/cm 3 , and =5.3×10 10 Hz. For maghemite nanoparticles, the size dependence of the anisotropy shows an increase with decreasing particle diameter consistent with data of other investigators. However this dependence is more rapid than the 1/ behavior typically used to discuss the size dependence of nanoparticle magnetic anisotropy. The magnetic field dependence of the magnetization of the nanoparticles below their blocking temperature indicates negligible coercivity for the 7.0 nm, 3.4 nm, and 2.5 nm maghemite samples. However, for the 6.3 nm maghemite and the Fe-Pt samples, significant coercivity is observed with their magnitudes increasing with decreasing temperatures below and reaching 400 Oe and 750 Oe at 2 K, respectively. Above the field dependence of the magnetization of all the samples was analyzed in two different ways: in terms of a modified La...

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“…Small α-Fe NPs use to exhibit anisotropy energies with one or two orders of magnitude larger [12,13] than that observed for bulk iron, whose value is = , it is possible to estimate the blocking temperature T B from the magnetic anisotropy. In this case, considering Fe NPs with diameter of 8 nm and K 5 10 5 ∼ × J/m 3 , we obtain T 400 B ∼ K. In this sense, the calculated T B seems to indicate that the particles may be already blocked at 300 K. Fig.…”

Section: Magnetic Behaviormentioning

confidence: 99%

Mechano-synthesis, structural and magnetic characterization, and heat release of α-Fe nanoparticles embedded in a wüstite matrix

Batista

Morales

Santos

et al. 2015

Journal of Magnetism and Magnetic Materials

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a b s t r a c tWe report a study of the structural and magnetic properties, as well as of the heat release, of an iron/ wüstite composite, prepared from iron powder and water by high energy mechanical milling. We identify that the produced sample consists of α-Fe nanoparticles embedded in a wüstite matrix and has high stability in time. Moreover, we observe that it presents noticeable features, as exchange bias effect at low temperatures and, when an alternating magnetic field is applied, its temperature reaches ∼46°C in ∼600 s. Thus, the results and the possibility of tuning the magnetic properties of α-Fe nanoparticles embedded in a wüstite matrix, through interface interactions, place this system as a very attractive candidate for biomedical applications such as magnetic hyperthermia agent for cancer therapy.

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Large enhancements of magnetic anisotropy in oxide-free iron nanoparticles

Cited by 23 publications

References 18 publications

Investigation of magnetically controlled water intake behavior of Iron Oxide Impregnated Superparamagnetic Casein Nanoparticles (IOICNPs)

Investigation of magnetically controlled water intake behavior of Iron Oxide Impregnated Superparamagnetic Casein Nanoparticles (IOICNPs)

Effects of Size and Size Distribution on the Magnetic Properties of Maghemite Nanoparticles and Iron-Platinum Core-Shell Nanoparticles

Mechano-synthesis, structural and magnetic characterization, and heat release of α-Fe nanoparticles embedded in a wüstite matrix

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