Asymmetric magnetic dots: A way to control magnetic properties

TL;DR

This study uses Monte Carlo simulations to explore how geometric asymmetry in magnetic dots influences their coercivity, remanence, and vortex behavior, revealing non-monotonic dependencies and potential for controlling magnetic chirality.

Contribution

It introduces a novel investigation of asymmetric magnetic dots, demonstrating how shape asymmetry affects magnetic properties and vortex dynamics, offering new ways to control magnetic behavior.

Findings

Non-monotonic dependence of coercivity and remanence on asymmetry parameter

Asymmetry influences vortex entry, exit, and chirality control

Shape asymmetry affects vortex formation and magnetic hysteresis

Abstract

We have used Monte Carlo simulations to investigate the magnetic properties of asymmetric dots as a function of their geometry. The asymmetry of round dots is produced by cutting off a fraction of the dot and is characterized by an asymmetry parameter $\alpha$. This shape asymmetry has interesting effects on the coercivity ($H_{c}$), remanence ($M_{r}$), and barrier for vortex and C- state formation. The dependences of $H_{c}$ and $M_{r}$ are non monotonic as a function of $\alpha$ with a well defined minima in these parameters. The vortex enters the most asymmetric part and exits through the symmetric portion of the dot. With increasing $\alpha $ the vortex formation starts with a C-state which persists for longer fields and the barrier for vortex exit diminishes with increasing asymmetry, thus providing control over the magnetic chirality. This implies interesting, naively-unexpected, magnetic behavior as a function of geometry and magnetic field.