Searcharxiv⌕ Search

arXiv · physics/0607117

The Stoner-Wohlfarth model of Ferromagnetism: Static properties

Abstract

Recent advances in high-density magnetic storage and spin electronics are based on the use of magnetic materials along with conventional microelectronic materials (metals, insulators and semiconductors). The unit information (bit) is stored as a magnetization state in some ferromagnetic ma rial (FM) and controlled with an external field altering the magnetization state. As device size is shrinking steadily toward the nanometer and the need to incr se its bandwidth prevails, racing toward higher frequencies is getting even more cha enging. In magnetic systems, denser storage leads to finer magnetic grains and small size leads to single magnetic domain physics. The Stoner-Wohlfarth model is the simplest model that describes adequately the physics of fine magnetic grains containing single domains and where magnetization state changes by rotation or switching (abrupt reversal). The SW model is reviewed and discussed with its consequences and potential app cations in the physics of magnetism and spin electronics.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

C. Tannous, J. Gieraltowski. 2008-04-25. The Stoner-Wohlfarth model of Ferromagnetism: Static properties. https://arxiv.org/abs/physics/0607117

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Optimization of curved vortex generator geometry for enhanced thermal performance in water-to-air finned-tube heat exchanger

In the study, the geometry of curved rectangular vortex generators (RVG) has been optimized to enhance heat transfer and overall performance of the analyzed water-to-air finned-tube heat exchanger (FTHE). The developed and validated conjugate numerical model includes a small section of the full-scale heat exchanger representing the computational domain, with fully developed velocity and temperature profiles specified at the inlet boundaries of the water. Four influential geometry parameters of the vortex generator were selected for the optimization; attack angle, curvature angle, axial position in the streamwise direction and height. The optimization process has been performed according to two criteria: maximization of heat transfer solely and maximization of heat transfer while considering the influence of pressure drop. Accordingly, one objective function related to the Colburn factor (j) and two objective functions combining the Colburn factor and the friction factor (f) were defined. The regression analysis has been used and the Central composite design of experiment was selected in order to obtain non-linear regression polynomial functions which were integrated into the investigated objectives. The optimization procedure has been performed using the genetic algorithm. Optimized configurations performance improvement was evaluated through comparison with the performance of the reference FTHE with plain fins. For the RVG configuration optimized according to the objective of maximizing heat transfer, the Colburn factor was enhanced by 53.1%. Optimizing the RVG configuration to maximize heat transfer while accounting for the influence of pressure drop resulted in an enhancement of the FTHE area goodness factor by 14.4% for one set of geometry parameters, and an enhancement of volume goodness factor by 26.5% for another.

physics.class-ph↗

Repeated Binary Direct Collinear Impacts Under Incremental Contact Laws With Residual Indentation: A Hybrid Systems Formulation

Incremental contact laws specify the normal contact force through a differential relation, possibly carrying an internal state, driven by the indentation and its rate. In some, the force is extinguished at a nonzero indentation, whether by plastic deformation or by an elastic aftereffect, so that a residual deformation remains at separation. Such laws sit uneasily within rigid body dynamics, which admits no deformation. The tension is tolerable when the indentation is small relative to the bodies, so that it may be carried constitutively rather than geometrically. Even then, the contact law alone does not determine the interaction of the bodies. Because force and indentation no longer vanish together, conditions for the commencement and termination of contact must be supplied separately. So must the fate of the deformation and internal state at separation, neither of which the equations of motion contain. This article formulates the repeated direct collinear impact of two convex bodies under external forces as a hybrid dynamical system. The contact interface is modeled as a massless element carrying the contact law and its state, coupled to the bodies through relative velocity and an interaction force dictated by the contact state. Consequently, all switching and resets are confined to the interface, leaving the geometry and the equations of motion of the bodies unaltered. The principal analytical properties of the resulting formulations are established, among them passivity and completeness; the branching of solutions at the onset and termination of contact is also examined. The framework is demonstrated through numerical simulations.

physics.class-ph↗