Minimal field requirement in precessional magnetization switching

TL;DR

This paper analyzes the minimal magnetic field needed for precessional magnetization switching, deriving an analytical expression for the critical field and exploring optimal field directions for fast switching.

Contribution

It provides an analytical expression for the critical switching field in small damping systems with biaxial anisotropy, advancing understanding of minimal field requirements.

Findings

Precessional switching occurs when phase space trajectories become unlocalized.

The critical switching field is analytically derived for small damping.

Applying the field along the medium axis optimizes for small field and rapid switching.

Abstract

We investigate the minimal field strength in precessional magnetization switching using the Landau-Lifshitz-Gilbert equation in under-critically damped systems. It is shown that precessional switching occurs when localized trajectories in phase space become unlocalized upon application of field pulses. By studying the evolution of the phase space, we obtain the analytical expression of the critical switching field in the limit of small damping for a magnetic object with biaxial anisotropy. We also calculate the switching times for the zero damping situation. We show that applying field along the medium axis is good for both small field and fast switching times.