Ratio of the rotational loss to hysteresis loss in ferrimagnetic powders

Bottoni, G.; Candolfo, D.; Cecchetti, A.; Masoli, F.

doi:10.1109/tmag.1974.1058337

Cited by 11 publications

(7 citation statements)

References 10 publications

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“…The spherical iron oxide nanoparticles with average diameter of 7.8 ± 1.8 nm are superparamagnetic at room temperature which means that particles cannot organize into 1-D chains purely by dipole magnetic interactions. It has been shown that magnetic coupling occurs in chain-like structures, causing an increase in coercivity. , For example, superparamagnetic nanoparticles that are covalently linked through their pole points are shown to form chains with induced magnetization moments . In this work, instead of using a molecular linker, we have decorated particles with polymers at low grafting density where the conformation of brush chains enable the brushes and lead to string formation.…”

Section: Resultsmentioning

confidence: 99%

Assembly of Polymer-Grafted Magnetic Nanoparticles in Polymer Melts

2012

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Hydrophobic iron oxide nanoparticles grafted with hydrophobic polymer chains of varying molecular weights and graft densities are synthesized to underpin the role of brush entanglement and dipolar forces on creating nanostructures. Grafting density on magnetic nanoparticles is controlled in graftingto method by changing the concentration of functionalized polymer in solution. The grafting density and brush length have varied systemically to observe the changes in nanostructures. Bridging between grafted chains and dipolar forces become effective only at low grafting density and result in long chains of particles. We demonstrate experimentally that structural transition of magnetic nanoparticles is controlled with the balance between grafted chain entanglements and dipolar forces.

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Section: Resultsmentioning

confidence: 99%

Assembly of Polymer-Grafted Magnetic Nanoparticles in Polymer Melts

2012

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“…5, i.e., the so-called ⌬ plot area. 9 A large reduction of the interactions is observed at Tϭ382°C, which is ascribed to various effects: a decrease of the magnetic moment of the crystallites, an increase of the fraction of superparamagnetic particles, and the disappearance of the amorphous phase which may favor the flux conduction. In the sample annealed at 530°C, which contains the lowest fraction of crystals dispersed in the amorphous matrix, the interactions are weaker than in the previous case and the difference between the curve at Tϭ22°C and Tϭ Ϫ196°C is more pronounced indicating the presence of a higher fraction of superparamagnetic crystallites at room temperature.…”

Section: Magnetic Interactionsmentioning

confidence: 99%

Evolution from soft to hard magnetic behavior in Co-based devitrified glassy alloy

Bottoni

Candolfo

Cecchetti

1996

Journal of Applied Physics

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“…It is well-known that aggregates made from magnetic nanoparticles show demagnetizing effect due to random dipole-dipole interaction between particles resulting in antiferromagnetically coupling. [32,[52][53][54] The magnetization curves at 5 K show that all samples have hysteresis with coercive field of 270 Oe. As expected, also in this case the magnetization of the chains increases faster with magnetic field compared to those of the isolated nanoparticles and of the aggregates.…”

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confidence: 97%