We review the physical properties of diluted magnetic semiconductors (DMS) of the type AII1−xMnxBVI (e.g., Cd1−xMnxSe, Hg1−xMnxTe). Crystallographic properties are discussed first, with emphasis on the common structural features which these materials have as a result of tetrahedral bonding. We then describe the band structure of the AII1−xMnxBVI alloys in the absence of an external magnetic field, stressing the close relationship of the sp electron bands in these materials to the band structure of the nonmagnetic AIIBVI ‘‘parent’’ semiconductors. In addition, the characteristics of the narrow (nearly localized) band arising from the half‐filled Mn 3d5 shells are described, along with their profound effect on the optical properties of DMS. We then describe our present understanding of the magnetic properties of the AII1−xMnxBVI alloys. In particular, we discuss the mechanism of the Mn++‐Mn++ exchange, which underlies the magnetism of these materials; we present an analytic formulation for the magnetic susc...

Diluted magnetic semiconductors

Zero-field splitting in metal complexes

This review compiles results of experimental and theoretical studies on thin films and quantum structures of semiconductors with randomly distributed Mn ions, which exhibit spintronic functionalities associated with collective ferromagnetic spin ordering. Properties of p-type Mn-containing III-V as well as II-VI, IV-VI, V-2 -VI3, I-II-V, and elemental group IV semiconductors are described, paying particular attention to the most thoroughly investigated system (Ga, Mn)As that supports the hole-mediated ferromagnetic order up to 190 K for the net concentration of Mn spins below 10%. Multilayer structures showing efficient spin injection and spin-related magnetotransport properties as well as enabling magnetization manipulation by strain, light, electric fields, and spin currents are presented together with their impact on metal spintronics. The challenging interplay between magnetic and electronic properties in topologically trivial and nontrivial systems is described, emphasizing the entangled roles of disorder and correlation at the carrier localization boundary. Finally, the case of dilute magnetic insulators is considered, such as (Ga, Mn)N, where low-temperature spin ordering is driven by short-ranged superexchange that is ferromagnetic for certain charge states of magnetic impurities.

Dilute ferromagnetic semiconductors: Physics and spintronic structures

Structural and magnetic properties have been studied for polycrystalline Zn1−xTMxO, where TM (transition metal ions)=Mn, Fe, and Co. No bulk ferromagnetism was observed for single-phase materials, contrary to the existing theories. Single-phase samples demonstrate paramagnetic Curie–Weiss behavior with antiferromagnetic interactions, similar to other diluted magnetic semiconductors. Nonoptimal synthesis conditions lead to formation of second phases that are responsible for spin-glass behavior {ZnMnO3 impurity for Zn1−xMnxO [S. Kolesnik et al., J. Supercond. 15, 251 (2002)]} or high-temperature ferromagnetic ordering [Co metal for Zn1−xCoxO with the Curie temperature TC>800 K or (Zn,Fe)3O4 for Zn1−xFexO with TC=440 K].

Structural and magnetic properties of transition metal substituted ZnO

Optical Properties of (Zn, Mn) and (Cd, Mn) Chalcogenide Mixed Crystals and Superlattices

The study of the s-d type exchange interaction in Zn1−xMnxSe mixed crystals

Magnetization and exchange constants in Zn1−xMnxSe

We report on the magnetic properties of the Cr-based diluted magnetic semiconductors ${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Cr}}_{\mathit{x}}$Se and ${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Cr}}_{\mathit{x}}$S (x0.01). The specific heat was measured in the temperature range 1.5T10 K and in magnetic fields up to 3 T, while the magnetization was measured at 2T40 K and B6 T. The magnetic behavior is neither that of Brillouin paramagnets [Mn, Co diluted magnetic semiconductors (DMS's)] nor of Van Vleck systems (Fe DMS's). It results from a strong, static Jahn-Teller (JT) distortion for the Cr ions. A simple crystal-field model, which includes the JT effect, provides an overall description of the experimental data, but some discrepancies remain.

Magnetic properties of Cr-based diluted magnetic semiconductors

The high-temperature magnetic susceptibility of random, diluted magnetic systems is discussed for magnetic ions having not only spin momentum but also nonvanishing orbital momentum. In particular, the magnetic susceptibility of ${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Fe}}_{\mathit{x}}$Se (${\mathrm{Fe}}^{2+}$, S=2,L+2) is reported in the temperature range 2--300 K. The nearest-neighbor Fe-Fe exchange interaction is estimated as ${J}_{\mathrm{NN}/{k}_{B}}$ =-22 K for ${\mathrm{Zn}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Fe}}_{\mathrm{x}}$Se and ${J}_{\mathrm{NN}/{k}_{B}=\mathrm{\ensuremath{-}}17.8}$ K for ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Fe}}_{\mathrm{x}}$Se.

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M. Demianiuk

Papers

The study of the s-d type exchange interaction in Zn1−xMnxSe mixed crystals

Magnetization and exchange constants in Zn1−xMnxSe

Magnetic properties of Cr-based diluted magnetic semiconductors

Magnetic susceptibility of iron-based semimagnetic semiconductors : high-temperature regime

The study of s-d exchange interaction in ZnFeSe semimagnetic semiconductor