Asymmetric magnetic dots: A way to control magnetic properties

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 . This shape asymmetry has interesting effects on the coercivity (Hc), remanence (Mr), and barrier for vortex and C- state formation. The dependences of Hc and Mr are non monotonic as a function of 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 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.