The two-spin model with dipolar interactions for the exchange coupled composite media

Abstract

We study exchange coupled composite (ECC) media where both the hard and soft coupled layers possess perpendicular anisotropy or one of the layers is superparamagnetic. Our model is used to demonstrate the effect of the dipolar interactions on the coercive field. A series of ECC samples with various thicknesses of Ru spacer is manufactured and analyzed. The structure of the samples prepared is CoPtCr-SiO2∕Ru∕CoPtCr-SiO2, with the composition varied around that of (CoPt17Cr10)90-(SiO2)10. The acquired experimental data are used to illustrate the significance of magnetostatic interactions between the two coupled magnetic layers.

Magnetostatic interactions and forces between cylindrical permanent magnets

“…where m 0 is the permeability of vacuum and J d the dipolar coupling integral defined in [5]. Following the computational method described in [1] the dipolar coupling integral J d can be expressed as…”

“…In a previous study [5], we introduced a semi-analytical formula for the magnetostatic interaction between two uniformly magnetized cylindrical elements of equal radius. In the present study, we first review briefly our subsequent achievement [6] of recasting the same formula in fully analytical form by means of elliptic integrals.…”

A simple approach to the First Order Reversal Curves (FORC) of two-phase magnetic systems

“…This approach has been successfully used in the description of magnetic composites [24][25][26] along the coercivity axis, by À g.…”

The influence of magnetostatic interactions in exchange-coupled composite particles

“…The key elements of the model, i.e. the magnetostatic coupling between sub-units (cylinders and shells), are described in references [11] (for core-shell interactions) and [12] (for cylinder-cylinder interactions). Following the standard Stoner-Wohlfarth approach [13], the magnetic energy of the system is minimized with respect to the magnetization vector orientation while the applied field varies.…”

“…Equations (6)(7)(8) were derived based on the integral form of the dipolar coupling factor, as discussed in [11] and [12]. The demagnetization factors of cylinders and shells can be expressed as combinations of elliptic integrals [11,16].…”