Ferromagnetic (Ga,Mn)N epilayers versus antiferromagnetic GaMn${}_3$N clusters

Abstract

Mn-doped wurtzite GaN epilayers have been grown by nitrogen plasma-assisted molecular beam epitaxy. Correlated SIMS, structural and magnetic measurements show that the incorporation of Mn strongly depends on the conditions of the growth. Hysteresis loops which persist at high temperature do not appear to be correlated to the presence of Mn. Samples with up to 2% Mn are purely substitutional Ga${}_{1-x}$Mn${}_x$N epilayers, and exhibit paramagnetic properties. At higher Mn contents, precipitates are formed which are identified as GaMn${}_3$N clusters by x-ray diffraction and absorption: this induces a decrease of the paramagnetic magnetisation. Samples co-doped with enough Mg exhibit a new feature: a ferromagnetic component is observed up to $T_c\sim 175$ K, which cannot be related to superparamagnetism of unresolved magnetic precipitates.

Revised version

References in corpus (5)

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• Theory of electrical spin injection: Tunnel contacts as a solution of the conductivity mismatch problem
• Molecular Beam Epitaxy of Wurtzite (Ga,Mn)N Films on Sapphire(0001) Showing the Ferromagnetic Behaviour at Room Temperature
• Carrier-induced ferromagnetism in p-Zn1-xMnxTe
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Cited by in corpus (8)

• Ferromagnetic Semiconductors: Moving Beyond (Ga,Mn)As
• Spinodal nanodecomposition in magnetically doped semiconductors
• Calculating the Curie Temperature reliably in diluted III-V ferromagnetic semiconductors
• Structural and paramagnetic properties of dilute Ga1-xMnxN
• Experimental probing of exchange interactions between localized spins in the dilute magnetic insulator (Ga,Mn)N
• High Curie temperatures in (Ga,Mn)N from Mn clustering
• Magneto-optical spectroscopy of (Ga,Mn)N epilayers
• Magnetotransport in phase-separated (Ga,Fe)N with $\gamma$'-Ga${}_y$Fe${}_{4-y}$N nanocrystals