Ion-beam modification of the magnetic properties of GaMnAs epilayers

Abstract

We study the controlled introduction of defects in GaMnAs by irradiating the samples with energetic ion beams, which modify the magnetic properties of the DMS. Our study focuses on the low-carrier-density regime, starting with as-grown GaMnAs films and decreasing even further the number of carriers, through a sequence of irradiation doses. We did a systematic study of magnetization as a function of temperature and of the irradiation ion dose. We also performed in-situ room temperature resistivity measurements as a function of the ion dose. We observe that both magnetic and transport properties of the samples can be experimentally manipulated by controlling the ion-beam parameters. For highly irradiated samples, the magnetic measurements indicate the formation of magnetic clusters together with a transition to an insulating state. The experimental data are compared with mean-field calculations for magnetization. The independent control of disorder and carrier density in the calculations allows further insight on the individual role of this two factors in the ion-beam-induced modification of GaMnAs.

arXiv comment9 pages, 9 figures

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Cited by in corpus (7)

• Rise and fall of defect induced ferromagnetism in SiC single crystals
• Precise tuning of the Curie temperature of (Ga,Mn)As-based magnetic semiconductors by hole compensation: Support for valence-band ferromagnetism
• Robustness of ferromagnetism in (In,Fe)Sb diluted magnetic semiconductor to variation of charge carrier concentration and Fermi level position
• Properties of group-IV-based ferromagnetic semiconductor GeFe: Growth temperature dependence, lattice constant, location of Fe atoms, and their relevance to the magnetic properties
• The nature of transport and ferromagnetic properties of the GaAs structures with the Mn δ-doped layer
• Tailoring the magnetism of GaMnAs films by ion irradiation
• Investigation of a possible electronic phase separation in the magnetic semiconductors Ga${}_{1-x}$Mn${}_x$As and Ga${}_{1-x}$Mn${}_x$P by means of fluctuation spectroscopy