Magnetic properties of core/shell nanoparticles with magnetic or nonmagnetic shells

Abstract

Magnetic properties of core/shell nanoparticles with magnetic or nonmagnetic shells for exchange bias in these systems in order to interpret the coupling effects for the core and shell in the core/shell system. Chemical intermixing at the interface leads to 'spin glass-like' behavior of the core/shell interface which affects the strength of coupling of the core and shell spins. In the random anisotropy model there is not so much of an effect when just high anisotropy cores and we do not expect a major difference between the superparamagnetic limits predicted by the Stoner-Wohlfarth and exchange models. Considering a bulging mode to occur in the core will have an effect on the results due to the magnetization reversal mechanisms.

Applications of exchange coupled bi-magnetic hard/soft and soft/hard magnetic core/shell nanoparticles

“…The above discussion neglects the effects of interparticle exchange and dipolar interactions. In particular, as discussed by Sebt et al, if core/shell nanoparticles are in physical contact with each other the exchange interactions could play an important role, where for example the coupling between two hard cores through their respective soft shells could lead to cooperative reversal and more complex effects such as random anisotropy effects [226]. Similarly, dipolar effects could also result in changes in the magnetic properties [226].…”

Magnetic anisotropy properties of Co1.2Fe1.8–xMnxO4(0.0 ⩽ x ⩽ 0.3) nanopowders: theory and experiment

“…On the other hand, the first calculation of the critical size for the single-domain configuration was performed by Kittel [20]. The single-domain takes place when the system size is of the same order of magnitude of the exchange length, a result of the high energetic cost for the formation of multiple domains [11,20,21]. The critical size d cr , which defines an upper limit for coherent rotation of magnetization, can be determined by the expression [22,23]…”