Remanent magnetic configurations in cylindrical nanodots

Abstract

Determining whether the magnetization of cylindrical nanodots is in a single domain configuration (SD) or a vortex state 𝑉𝑋 is crucial in a wide range of interdisciplinary applications. In this work we investigate the SD and 𝑉𝑋 existence, and their coexistence, in terms of the nanodot diameter (𝐷) and its saturation magnetization (𝑀𝑆 ) for different thicknesses, by means of micromagnetic simulations. We determine the stable magnetic configurations at remanence, from both in plane and out of plane hysteresis loops. Additionally, we investigate the vortex core radius 𝑅𝑉 in terms of different parameters considered. We find that 𝑅𝑉 is strongly dependent on the thickness and the saturation magnetization but the dependence is weaker on the diameter, vanishing for the larger ones. For the range of parameters studied in this work, we find that 𝑅𝑉 is diameter independent for 𝐷 ≳ 100 nm.