A. V. Molchanov

Ferromagnetism of manganese-doped InSb alloys

InSb samples containing 0.22–1.42 wt % manganese were synthesized and identified. The unit cell parameter decreased as the manganese concentration increased. The samples contained microinclusions of manganese antimonides. Electrical and magnetic measurements showed two ferromagnetic phases (In1−xMnxSb solid solution with Tc ∼ 7 K and MnSb with Tc ∼ 580 K) and a ferrimagnetic phase (Mn2Sb). The samples had p-type conductivity with a charge carrier concentration of about 1020cm−3. The semiconductor conductivity was observed at low temperatures and changed to the metal conductivity with temperature elevation.

Synthesis and magnetic properties of Mn-doped Cd0.1Zn0.9GeAs2 solid solutions

Homogeneous crystals of diluted magnetic semiconductor solid solution Zn0.9Cd0.1GeAs2 doped with 0, 1.13 and 2.65 mass% of Mn were synthesized. The grown crystals were characterized by atomic absorption and synchrotron x-ray powder diffraction analyses showing that the lattice parameter of the sample crystals are closely related to GaAs. Measurements of magnetic and transport properties were performed in the temperature range of 4–400 K using steady and pulsed magnetic fields up to B = 50 and 150 kG, respectively. The ferromagnetic Curie temperature of the sample crystals was found to be about 350 K. The magnetic ordering is attributed to the presence of MnAs clusters with mean size ~3.8 nm in the ferromagnetic phase. Influence of paramagnetic Mn2+ ions on magnetic properties of the crystals was observed only at low temperatures and was explained by the p–d interaction between charge-carrying holes and localized Mn moments.

Dilute magnetic semiconductor: Magnesium-doped Zn0.9Cd0.1GeAs2

Dilute magnetic semiconductors based on manganese-doped Zn0.9Cd0.1GeAs2 solid solution with various doping levels were synthesized. Their Curie point in 5-T magnetic field was 349 K. Ferromagnetic ordering in these semiconductors was due to MnAs nanoclusters, whose sizes were 3.7–3.8 nm.

Growth and structure of ZnSnAs2 crystals

High-quality ZnSnAs2 (I) single crystals have been grown. The unit cell parameters of compound I have been refined (a = b = 5.8360(1), c = 11.686(2) Å), and its crystal structure has been determined.

Edge absorption and light propagation in single crystals of Zn1−x Cd x As2 solid solutions

The transmittance of Zn1−xCdxAs2 anisotropic single crystals in their transparency region is found to depend on the incident light polarization, photon energy, and sample thickness. This effect is shown to be associated with light scattering in Zn1−xCdxAs2, which can be understood in terms of the crystal structure of the monoclinic crystals. The fundamental absorption edge in Zn1−xCdxAs2 is dominated by an indirect forbidden transition for the E ‖ c polarization and by a direct forbidden transition for E ⊥ c.

Optical and photoelectric properties of monoclinic Zn1 − x Cd x As2 crystals

The first data are presented on the band structure of monoclinic Zn1 − xCdxAs2 crystals. The fundamental absorption edge of Zn1 − xCdxAs2 for the E ‖ c polarization is shown to be dominated by an indirect allowed transition for absorption coefficients α‖ < 6 cm−1 and by a direct allowed transition for α‖ > 6 cm−1, both transitions involving excitonic levels. The absorption edge for E ⊥ c is due to a direct forbidden transition with the participation of excitonic levels. We have determined the band gap values for these transitions in the temperature range 80–300 K, the exciton binding energy, and the ionization energies of four deep acceptor levels produced in the band gap by structural defects.

Band structure of the diluted magnetic semiconductor MnxCd1−xGeAs2

The electron-density-functional approach is used to calculate the band structure of the CdGeAs2 semiconductor and the diluted magnetic semiconductor MnxCd1−xGeAs2, which has a ferromagnetic structure at x = 0.06. The results indicate that the incorporation of Mn increases the band gap at its center and leads to the formation of a band derived from Mn levels, whose energy is a weak function of wave vector. The calculation results agree with experimental data.

Synthesis, structures, and electrophysical properties of single crystals of solid solutions CdGeAs2:Mn(x) and Cd0.964Zn0.036GeAs2:Mn(x)

AbstractSingle crystals of the solid solutions CdGeAs2:Mn(x) and Cd0.964Zn0.036GeAs2:Mn(x) have been grown by the vertical Bridgman method. An X-ray diffraction study has demonstrated that Cd0.964Zn0.036GeAs2 (I), Cd0.964Zn0.036GeAs2:Mn (1.5 wt%) (II), and Cd0.964Zn0.036GeAs2:Mn (2.18 wt %) (III) retain the CdGeAs2 structure (tetragonal system, space group I

Phase transition of the new ferromagnet Cd1-xMnxGeAs2 at high pressures (0.9-4.7 GPa)

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