The ellipsometry measurements (in the energy range $E=0.5–5.0\mathrm{eV}$) on cleavage surfaces of single crystals, the measurements of the absorption and reflectance spectra $(E=0.04–0.8\mathrm{eV})$, electrical resistivity, and magnetic susceptibility were carried out for determination of peculiarities of the fundamental absorption spectrum and the conductivity mechanism in $\mathrm{Ca}\mathrm{Mn}{\mathrm{O}}_{3-\delta }$ single crystals. The energy of fundamental absorption edge associated with the direct transitions was determined as $E_{\mathrm{g}}=1.55\mathrm{eV}$. The absorption band with two maxima at 2.2 and $3.1\mathrm{eV}$ corresponding to the charge transfer transitions was revealed. The polaron band at $0.7\mathrm{eV}$ was discovered and polaron parameters were determined. Peculiarities of IR absorption and dc conductivity of $\mathrm{Ca}\mathrm{Mn}{\mathrm{O}}_{3-\delta }$ in dependence on oxygen stoichiometry are determined by the superposition of hopping and band conductivity of spin-lattice polarons, and by additional localization of charge carriers under oxygen vacancies ordering.

From the various aspects of spintronics the review highlights the area devoted to the creation of new functional materials based on magnetic semiconductors and demonstrates both the main physical phenomena involved and the technical possibilities of creating various devices: maser, p-n diode with colossal magnetoresistance, spin valve, magnetic lens, optical modulators, spin wave amplifier, etc. Particular attention is paid to promising research directions such as ultrafast spin transport and THz spectroscopy of magnetic semiconductors. Special care has been taken to include a brief theoretical background and experimental results for the new spintronics approach employing magnetostrictive semiconductors—strain-magnetooptics. Finally, it presents top-down approaches for magnetic semiconductors. The mechano-physical methods of obtaining and features of the physical properties of high-density nanoceramics based on complex magnetic oxides are considered. The potential possibility of using these nanoceramics as an absorber of solar energy, as well as in modulators of electromagnetic radiation, is shown.

Analysis of the experimental optical spectra of CuO nanoparticles with the electronic structure characterized by strong electron correlations has revealed the appearance of unusual states inside the...

Transport, magnetic, magneto-optical (Kerr effect) and optical (light absorption)properties have been studied in an oriented polycrystalline La 0.67 Ca 0.33 MnO 3 film which shows colossal magnetoresistance. The correlations between these properties are presented. A giant change in infrared light transmission (more than a thousand-fold decrease) is observed on crossing the Curie temperature (about 270 K) from high to low temperature. Large changes in transmittance in a magnetic field were observed as well. The giant changes in transmittance and the large magnetotransmittance can be used for development of IR optoelectronic devices controlled by thermal and magnetic fields. Required materialcharacteristics of doped manganites for these devices are discussed.

A 0.1–0.15-eV displacement of the fundamental absorption edge in the optical absorption spectra of nanocrystalline oxide n-CuO (relative to the position of the fundamental absorption edge in the...