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

S. Haghgoo (1) , M. Cubukcu (1) , H. J. von Bardeleben (1) , L. Thevenard (1) , A. Lemaître (2) , Catherine Gourdon (1)

1 INSP - Institut des Nanosciences de Paris
2 LPN - Laboratoire de photonique et de nanostructures

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.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

S. Haghgoo, M. Cubukcu, H. J. von Bardeleben, L. Thevenard, A. Lemaître, et al.. Exchange constant and domain wall width in (Ga,Mn)(As,P) films with self-organization of magnetic domains. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2010, 82 (4), ⟨10.1103/PhysRevB.82.041301⟩. ⟨hal-00482380⟩