Magnetic nanoparticles are an important example of a mul- tiscale problem. 9, 10 We will discuss the origin of the exchange bias effect later in this article. O'Handley, Modern Magnetic Materials: Principles and Applications (Wiley, 1999). In order to explore an alternative strategy to design exchange-biased magnetic nanostructures, bimagnetic core/shell nanoparticles have been fabricated by a. in coreshell exchange bias systems due to their potential application in increasing the superparamagnetic limit of small magnetic nanoparticles used in data storage systems. Winkler, Nanotechnology 25, 355704 (2014) Baaziz et al., reported the high exchange bias (H E 4. Charap, Physics of Magnetism (Wiley, New York, 1964)ĭ. In this chapter, we discuss the new properties found in core/shell bimagnetic nanoparticles and analyze the main characteristics that have to be taken into account to design a system with a particular response. Hysteresis measurements of core-shell particles at 5 K. The magnetic response changes depend on the magnetic ordering and anisotropy of the phases, the core size and shell thickness, the quality of the interface, and the strength of the interface exchange coupling. We have used the Monte Carlo simulation technique to investigate the effect of an antiferromagnetic shell on the exchange bias and the coercive fields of composite magnetic nanoparticles with core/shell morphology. The magnetization curves of monodisperse Fe/Fe3O4 core-shell and Fe3O4 hollow-shell nanoparticles reveal an unusual exchange-bias effect. The number of parameters that governs the magnetic behavior grows enormously and the opportunity to manipulate, control, and understand the role played by each one of them, opens a wide range of possibilities to design novel materials with suited properties. The presence of interfaces in core/shell bimagnetic nanoparticles introduces additional interactions that could radically modify the static and dynamic magnetic behavior of the systems. nanomaterials core/shell nanostructures exchange bias interparticle interactions 1. The non-saturation of magnetization up to 50 KOe applied magnetic field is due to its AFM core and surface disordered spins. The advances in the physical and chemical fabrication methods have enabled the possibility to produce artificial nanostructures whose properties are different from that of their constituent materials. In nanoparticles, exchange bias like behaviour is due to the coreshell interaction of NPs and reported extensively for AFM nanoparticles 5, 28, 29, 43, 6972. Bi-magnetic nanoparticles (NPs) with core-shell morphology are gaining considerable interest both in research and technological applications.
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