Zero-field magnetization reversal of two-body Stoner particles with dipolar interaction

TL;DR

This paper predicts that by engineering dipole-dipole interactions in a system of two synchronized Stoner particles, the critical switching field can be dramatically reduced or even eliminated, enabling faster and more efficient magnetic reversal.

Contribution

It introduces a novel method to lower the critical switching field in nanomagnetic systems by manipulating dipolar interactions between two particles.

Findings

Critical switching field can be reduced to zero.

Dipolar interaction engineering enables faster magnetization reversal.

Feasibility demonstrated with cobalt nanoparticles.

Abstract

Nanomagnetism has recently attracted explosive attention, in particular, because of the enormous potential applications in information industry, e.g. new harddisk technology, race-track memory[1], and logic devices[2]. Recent technological advances[3] allow for the fabrication of single-domain magnetic nanoparticles (Stoner particles), whose magnetization dynamics have been extensively studied, both experimentally and theoretically, involving magnetic fields[4-9] and/or by spin-polarized currents[10-20]. From an industrial point of view, important issues include lowering the critical switching field $H_c$, and achieving short reversal times. Here we predict a new technological perspective: $H_c$ can be dramatically lowered (including $H_c=0$) by appropriately engineering the dipole-dipole interaction (DDI) in a system of two synchronized Stoner particles. Here, in a modified Stoner-Wohlfarth (SW) limit, both of the above goals can be achieved. The experimental feasibility of realizing our proposal is illustrated on the example of cobalt nanoparticles.