Domain walls in (Ga,Mn)As diluted magnetic semiconductor

TL;DR

This study combines experimental imaging and theoretical modeling to analyze magnetic domain walls in (Ga,Mn)As, revealing how anisotropies influence wall structure and orientation-dependent widths.

Contribution

It provides the first direct imaging of domain wall profiles in (Ga,Mn)As and links these profiles to microscopic anisotropy effects through combined experimental and theoretical approaches.

Findings

Domain wall widths vary from 40 nm to 120 nm depending on orientation.

Domain walls are of the Néel type and change character with temperature.

Anisotropy competition influences domain wall structure and orientation.

Abstract

We report experimental and theoretical studies of magnetic domain walls in an in-plane magnetized (Ga,Mn)As dilute moment ferromagnetic semiconductor. Our high-resolution electron holography technique provides direct images of domain wall magnetization profiles. The experiments are interpreted based on microscopic calculations of the micromagnetic parameters and Landau-Lifshitz-Gilbert simulations. We find that the competition of uniaxial and biaxial magnetocrystalline anisotropies in the film is directly reflected in orientation dependent wall widths, ranging from approximately 40 nm to 120 nm. The domain walls are of the N\'eel type and evolve from near-$90^{\circ}$ walls at low-temperatures to large angle [1$\bar{1}$0]-oriented walls and small angle [110]-oriented walls at higher temperatures.