Enhancing $T_c$ in ferromagnetic semiconductors

Abstract

We theoretically investigate disorder effects on the ferromagnetic transition ('Curie') temperature $T_c$ in dilute III${}_{1-x}$Mn${}_x$V magnetic semiconductors (e.g. Ga${}_{1-x}$Mn${}_x$As) where a small fraction ($x\approx 0.01-0.1$) of the cation atoms (e.g. Ga) are randomly replaced by the magnetic dopants (e.g. Mn), leading to long-range ferromagnetic ordering for $T<T_c$. We find that $T_c$ is a complicated function of at least eight different parameters including carrier density, magnetic dopant density, and carrier mean free path; nominally macroscopically similar samples could have substantially different Curie temperatures. We provide simple physically appealing prescriptions for enhancing $T_c$ in diluted magnetic semiconductors, and discuss the magnetic phase diagram in the system parameter space.

5 pages with 4 figures

References in corpus (10)

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Cited by in corpus (8)

• Theory of ferromagnetic (III,Mn)V semiconductors
• Prospects of high temperature ferromagnetism in (Ga,Mn)As semiconductors
• Theory of carrier mediated ferromagnetism in dilute magnetic oxides
• Influence of non-local exchange on RKKY interactions in III-V diluted magnetic semiconductors
• Reversible room-temperature ferromagnetism in Nb-doped SrTiO3 single crystals
• Metal-insulator transition by isovalent anion substitution in Ga1-xMnxAs: Implications to ferromagnetism
• The influence of structural short-range order on the phase diagrams of diluted FCC magnet with arbitrary spin and modified RKKY interaction
• Effects of dilution and disorder on magnetism in diluted spin systems