Deconvoluting Reversal Modes in Exchange Biased Nanodots

TL;DR

This paper investigates the microscopic reversal modes in exchange-biased Fe/FeF2 nanodots, revealing how different reversal behaviors influence the overall exchange bias and how these modes can be modulated.

Contribution

It deconvolutes the ensemble-averaged exchange bias into local biases associated with distinct reversal modes in nanodots, highlighting the impact of vortex states and domain walls.

Findings

Single domain dots show a simple loop shift.

Vortex state dots exhibit asymmetric shifts in nucleation and annihilation fields.

Exchange bias can modify the fraction of dots in each reversal mode.

Abstract

Ensemble-averaged exchange bias in arrays of Fe/FeF2 nanodots has been deconvoluted into local, microscopic, bias separately experienced by nanodots going through different reversal modes. The relative fraction of dots in each mode can be modified by exchange bias. Single domain dots exhibit a simple loop shift, while vortex state dots have asymmetric shifts in the vortex nucleation and annihilation fields, manifesting local incomplete domain walls in these nanodots as magnetic vortices with tilted cores.