Core/Shell Nanoparticles: Classes, Properties, Synthesis Mechanisms, Characterization, and Applications

In this chapter, we will restrict our attention to the ferrites and a few other closely related materials. The great interest in ferrites stems from their unique combination of a spontaneous magnetization and a high electrical resistivity. The observed magnetization results from the difference in the magnetizations of two non-equivalent sub-lattices of the magnetic ions in the crystal structure. Materials of this type should strictly be designated as “ferrimagnetic” and in some respects are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present. We shall not adhere to this special nomenclature except to emphasize effects, which are due to the existence of the sub-lattices.

Ferromagnetic materials

http://files.janapv.webnode.cz/200000097-8a03f8afdf/ex_bias_nano.pdf

Exchange bias in nanostructures

We developed two-step solution-phase reactions to form hybrid materials of Mn3O4 nanoparticles on reduced graphene oxide (RGO) sheets for lithium ion battery applications. Mn3O4 nanoparticles grown selectively on RGO sheets over free particle growth in solution allowed for the electrically insulating Mn3O4 nanoparticles wired up to a current collector through the underlying conducting graphene network. The Mn3O4 nanoparticles formed on RGO show a high specific capacity up to ~900mAh/g near its theoretical capacity with good rate capability and cycling stability, owing to the intimate interactions between the graphene substrates and the Mn3O4 nanoparticles grown atop. The Mn3O4/RGO hybrid could be a promising candidate material for high-capacity, low-cost, and environmentally friendly anode for lithium ion batteries. Our growth-on-graphene approach should offer a new technique for design and synthesis of battery electrodes based on highly insulating materials.

Mn3O4-Graphene Hybrid as a High Capacity Anode Material for Lithium Ion Batteries

https://www.andrew.cmu.edu/user/dl0p/laughlin/pdf/PMS.pdf

Amorphous and nanocrystalline materials for applications as soft magnets

/pdf/descricao-da-magnetoresistencia-faz-15-anos-5ftayl957u.pdf

Descrição da magnetoresistência faz 15 anos

A phenomenological approach to study the effect of uniaxial anisotropy on the magnetization of ferromagnetic nanoparticles

Magneto-impedance relaxation in amorphous wires and ribbons

Alternating current Joule heating is explored to produce magnetic wires consisting of two different magnetic phases, one soft, with coercivities of the order of few A/m, and other harder, with coercivities around 10 kA/m. The effect of current frequency and intensity in the formation of the two-phase composite material is investigated. Although the two phases are formed due to different loss parameters along the wire length (basically due to thermal contacts), there is also an important influence of the skin effect.

Marcelo Knobel

Papers

Descrição da magnetoresistência faz 15 anos

A phenomenological approach to study the effect of uniaxial anisotropy on the magnetization of ferromagnetic nanoparticles

Magneto-impedance relaxation in amorphous wires and ribbons

Two Phase Magnetic Wire Obtained By High Frequency Current Annealing

Influence of Induced Anisotropy and Magnetostriction in the Magnetoimpedance and Its Aftereffect in CoFeSiB Amorphous Ribbons