R. I. Zainullina

Kinetic properties of an La0.85Ba0.15MnO3 single crystal

We report the temperature and magnetic field dependence of resistivity, Hall effect, and thermopower of an La0.85Ba0.15MnO3 single crystal. It is found that the Fermi level lies in the energy gap and conduction is by hopping. In the ferromagnetic state the variable range hopping prevails, while in the paramagnetic state hopping between nearest neighbours dominates. The small value of the activation energy of thermopower is explained by a weak asymmetry of density of states near the Fermi energy.

Optical and magneto-optical effects in Hg{sub 1-x}Cd{sub x}Cr{sub 2}Se{sub 4} (0 ⩽ x ⩽ 1) single crystals

The concentration, temperature, and magnetic-field dependences of the magnetoreflection and magnetotransmission of natural light in the infrared spectral range and the Kerr effect in single crystals of ferromagnetic Hg1-xCdxCr2Se4 (0 ⩽ x ⩽ 1) spinels have been studied. A relationship of the magneto-optical properties to the electronic band structure of spinels has been established. The most significant changes in the spectra of magnetoreflection, magnetotransmission, and the Kerr effect are shown to be observed for 0.1 < x < 0.25 and are attributable to a rearrangement of the band structure as the composition changes.

Optical and magneto-optical effects in Hg1-xCdxCr2Se4 (0 ⩽ x ⩽ 1) single crystals

The concentration, temperature, and magnetic-field dependences of the magnetoreflection and magnetotransmission of natural light in the infrared spectral range and the Kerr effect in single crystals of ferromagnetic Hg1-xCdxCr2Se4 (0 ⩽ x ⩽ 1) spinels have been studied. A relationship of the magneto-optical properties to the electronic band structure of spinels has been established. The most significant changes in the spectra of magnetoreflection, magnetotransmission, and the Kerr effect are shown to be observed for 0.1 < x < 0.25 and are attributable to a rearrangement of the band structure as the composition changes.

Electron Doped CaMnO3: Mn-Site Substitution versus Ca-Site Substitution

The magnetic, transport, optical, and elastic properties of the electron-doped manganites CaMn1-xMxO3 with Mn-site doping (M=Mo or W, x≤0.20) are studied and the results are compared with those of Ca-site substituted manganites with the same Mn3+ concentration. If Mn3+ concentration is lees than 10%, the charge carriers localization due to lattice distortions in the Ca-site doped samples is stronger than the localization caused by magnetic dilution in the case of Mn-site substitution. At higher Mn3+ concentration, the magnetic dilution plays a key role.

Optical Properties of FeGe 2 Single Crystal

The reflection spectra of FeGe2 single crystal in a wide spectral region and in the temperature range from 80 to 310 K are studied. The energy of plasma oscillations, the relaxation frequency of charge carriers, and phonon frequencies are determined. Anisotropy of the optical properties is studied. It is shown that the phase transition from the collinear antiferromagnetic structure to the spiral one is accompanied by a significant rearrangement of electronic states.

Elastic properties of La0.82Ca0.18MnO3 single crystal

The temperature dependences of the velocity of longitudinal sound waves and the internal friction in a La0.82Ca0.18MnO3 single crystal with the Curie temperature TC = 181 K have been studied. As temperature decreases, the single crystal is shown to undergo the transition from the pseudocubic O* to the Jahn–Teller O’ phase at T ~ 254 K and the reverse transition from O’ to O* phase at T ~ 84 K. The velocity of sound and the internal friction in the O’ phase are found to be significantly smaller than those in the O* phase.

Optical properties of the Cr5S6 single crystal

Results of the investigation of optical density spectra of Cr5S6 single crystals in the infrared region have been presented. A comparative analysis of the temperature dependences of the magnetization and the light absorption has been performed. Physical mechanisms to explain the specific features of the spectral and temperature dependences of the optical density have been proposed.

Magnetooptical Properties of Hg1-xCdxCr2Se4 Solid Solutions

Influence of the substitution of Hg by Cd on Kerr effect, magnetoreflection, and magnetotransmission of unpolarized light for Hg1-xCdxCr2Se4 (0≤x≤1) single-crystals is studied. The changes in the magnetooptical properties of the ferromagnetic spinels are shown to occur in compositions with x>0.1. The giant values of magnetooptical effects in Hg1-xCdxCr2Se4 spinels can be used in the magnetooptoelectronics.

Elastic and magnetic properties of single-crystal La0.4

Results are reported on the experimental investigation of the temperature dependences of the magnetization, velocity of longitudinal sound, and internal friction of single-crystal La0.4Pr0.3Ca0.3MnO0.3. In the paramagnetic region, extended temperature hysteresis of the sound velocity has been revealed, which is due to a nonequilibrium state of the crystal structure of the compound.