Exchange constant and domain wall width in (Ga,Mn)(As,P) films with self-organization of magnetic domains

TL;DR

This study investigates how phosphorus incorporation in (Ga,Mn)As films influences magnetic domain structures, exchange interactions, and domain wall properties, revealing improved magnetic quality and self-organized domain patterns in the material.

Contribution

It demonstrates the first observation of self-organized magnetic domains in (Ga,Mn)As:P and quantifies how phosphorus affects exchange constants and domain wall widths.

Findings

Self-organized magnetic domains observed in (Ga,Mn)As:P.

Increased domain wall width parameter with phosphorus incorporation.

No significant change in Mn-Mn coupling with P concentration.

Abstract

The incorporation of Phosphorus into (Ga,Mn)As epilayers allows for the tuning of the magnetic easy axis from in-plane to perpendicular-to-plane without the need for a (Ga,In)As template. For perpendicular easy axis, using magneto-optical imaging a self-organized pattern of up- and down-magnetized domains is observed for the first time in a diluted magnetic semiconductor. Combining Kerr microscopy, magnetometry and ferromagnetic resonance spectroscopy, the exchange constant and the domain wall width parameter are obtained as a function of temperature. The former quantifies the effective Mn-Mn ferromagnetic interaction. The latter is a key parameter for domain wall dynamics. The comparison with results obtained for (Ga,Mn)As/(Ga,In)As reveals the improved quality of the (Ga,Mn)As$_{1-y}$P$_y$ layers regarding domain wall pinning, an increase of the domain wall width parameter and of the effective Mn-Mn spin coupling. However, at constant Mn doping, no significant increase of this coupling is found with increasing P concentration in the investigated range.