Phenomenological theory of magnetization reversal in nanosystems with competing anisotropies

TL;DR

This paper develops a micromagnetic theory to analyze how competing anisotropies influence magnetization reversal in nanomagnetic systems, providing phase diagrams and detailed profiles of domain walls and stripe domains.

Contribution

It introduces a comprehensive micromagnetic model for nanomagnets with competing anisotropies, including phase diagrams and analysis of domain structures and reversal processes.

Findings

Magnetic phase diagrams classify different reversal types.

Magnetization profiles of domain walls are highly sensitive to anisotropies.

Stripe domain parameters depend on applied bias field.

Abstract

The interplay between intrinsic and surface/interface-induced magnetic anisotropies strongly in- fluences magnetization processes in nanomagnetic systems. We develop a micromagnetic theory to describe the field-driven reorientation in nanomagnets with cubic and uniaxial anisotropies. Spin configurations in competing phases and parameters of accompanying multidomain states are calculated as functions of the applied field and the magnetic anisotropies. The constructed magnetic phase diagrams allow to classify different types of the magnetization reversal and to provide detailed analysis of the switching processes in magnetic nanostructures. The calculated magnetization profiles of isolated domain walls show that the equilibrium parameters of such walls are extremely sensitive to applied magnetic field and values of the competing anisotropies and can vary in a broad range. For nanolayers with perpendicular anisotropy the geometrical parameters of stripe domains have been calculated as functions of a bias field. The results are applied to analyse the magnetization processes as observed in various nanosystems with competing anisotropies, mainly, in diluted magnetic semiconductor films (Ga,Mn)As.