Electronic phase separation in insulating (Ga,Mn)As with low compensation: Super-paramagnetism and hopping conduction

Abstract

In the present work, low compensated insulating (Ga,Mn)As with 0.7% Mn is obtained by ion implantation combined with pulsed laser melting. The sample shows variable-range hopping transport behavior with a Coulomb gap in the vicinity of the Fermi energy, and the activation energy is reduced by an external magnetic field. A blocking super-paramagnetism is observed rather than ferromagnetism. Below the blocking temperature, the sample exhibits a colossal negative magnetoresistance. Our studies confirm that the disorder-induced electronic phase separation occurs in (Ga,Mn)As samples with a Mn concentration in the insulator-metal transition regime, and it can account for the observed superparamagnetism and the colossal magnetoresistance.

arXiv comment14 pages, 7 figures

References in corpus (20)

• Colossal Magnetoresistant Materials: The Key Role of Phase Separation
• Dilute ferromagnetic semiconductors: Physics and spintronic structures
• Effects of Disorder on Ferromagnetism in Diluted Magnetic Semiconductors
• Origin and control of high-temperature ferromagnetism in semiconductors
• Visualizing Critical Correlations near the Metal-Insulator Transition in Ga1-xMnxAs
• Experimental probing of the interplay between ferromagnetism and localisation in (Ga,Mn)As
• Achieving High Curie Temperature in (Ga,Mn)As
• Sensitive SQUID magnetometry for studying nano-magnetism
• Spinodal nanodecomposition in magnetically doped semiconductors
• Transition temperature of ferromagnetic semiconductors: a dynamical mean field study
• Fe implanted ferromagnetic ZnO
• Monte Carlo Study of Ferromagnetism in (III,Mn)V Semiconductors
• Ferromagnetism in Ga1-xMnxP: evidence for inter-Mn exchange mediated by localized holes within a detached impurity band
• Interplay between carrier localization and magnetism in diluted magnetic and ferromagnetic semiconductors
• Spin-glass-like behavior of Ge:Mn
• Control of Coercivities in (Ga,Mn)As Thin Films by Small Concentrations of MnAs Nanoclusters
• All-wurtzite (In,Ga)As-(Ga,Mn)As core-shell nanowires grown by molecular beam epitaxy
• Interplay between localization and magnetism in (Ga,Mn)As and (In,Mn)As
• MnSi${}_{1.7}$ nanoparticles embedded in Si: Superparamagnetism with a collective behavior
• Wurtzite (Ga,Mn)As nanowire shells with ferromagnetic properties

Cited by in corpus (2)

• Cubic anisotropy in high homogeneity thin (Ga,Mn)As layers
• Phase diagram of a ferromagnetic semiconductor. The origin of superparamagnetism