Effective g-factor for two strongly exchange-coupled magnetization vectors

Abstract

A magnetic resonance without recourse to the linear response theory (as first formulated for the dynamics of nuclear induction by Bloch) can be characterized in terms of a limit cycle whose period is equal to the inverse of the Larmor frequency. This fact is used to investigate the effective g-factor for a system of two strongly coupled, macroscopic magnetizations (generally, with unequal g-factors) through an isotropic, spatially uniform (expressible as a mean field) exchange interaction. The result rigorously confirms Bloembergen and Rowlands' prediction, and is verified explicitly by a computer experiment.