Magnonic Crystal with Strips of Magnetic Nanoparticles: Modeling and Experimental Realization via a Dip-Coating Technique

In this article, we describe a magnonic crystal formed by magnetite nanoparticles. The periodic strip-like structure of the nanoparticles was fabricated on the surface of thin yttrium iron garnet single-crystal film grown on a gallium–gadolinium garnet substrate via dip-coating techniques. It was shown that such periodic structure induces the formation of the bandgaps in the transmission spectra of magnetostatic surface spin-waves (MSSW). The structure was simulated by the transfer matrix method. Spin-wave detection has been carried out by using a pair of microwave antennas and a vector network analyzer.

Отрицательное магнитосопротивление в структуре n-InSb/ЖИГ

It is shown that for the n-InSb/YIG/GGG (YIG - yttrium iron garnet, GGG - gallium-gadolinium garnet) structure in the tangent to the substrate plane geometry of magnetization (H <10 kOe) at a temperature T≈300 K the magnetoresistance of about 1% is negative, while for n-InSb/GGG structure, in the same magnetization geometry, the magnetoresistance is positive (an increase in electrical resistance in a magnetic field). The negative magnetoresistance effect in the InSb/YIG/GGG structure is due to the influence of the YIG magnetization on the conduction electrons of InSb (proximity effect) and the magnitude of the effect is determined by the value of YIG magnetization and parameters of InSb films.

Cвойства пленок на основе наноразмерных и субмикронных частиц InSb, пассивированных CdS

In the InSb film fabricated by thermal evaporation on the CdS single crystal, growth of reflection in the infrared region similar to plasma resonance in the single crystals has observed. Raman spectra demonstrate that the ratio of amorphous and crystalline phases is approximately constant for InSb films on the CdS substrate, which is not typical for the InSb film on gallium gadolinium garnet. The current – voltage characteristics of the InSb film on CdS as well as the annealed layer of InSb (core)–CdS (shell) quantum dots are linear and become sensitive to illumination.

Growing of Thick Single-Crystalline La-Substituted Yttrium-Iron Garnet Films with Reproducible Parameters

Basic principles of growing the thick (35–60 мm) single-crystalline La-substituted yttrium-iron garnet (Y3−xLaxFe5O12, La :YIG) films with reproducible parameters have been formulated. La :YIG films are grown on gallium-gadolinium garnet (Gd3Ga5O12) substrates from a supercooled melt-solution (MS) consisting of Y2O3, La2O3, and Fe2O3 oxides and the PbO–B2O3 solvent. In order to minimize the implantation of Pb2+ ions into the films, which degrades the film quality, the epitaxy has to be performed at high temperatures and a low MS supercooling. It is found that, in order to maintain a constant growth rate of La :YIG films with reproducible parameters, a large MS mass (10–16 kg) has to be used, and the MS temperature has to be permanently lowered at a rate of 0.042 K/min.

Теплоемкость легированного эрбием галлий-гадолиниевого граната

In this paper, we compared the results of a heat capacity study of an erbium-doped gallium gadolinium garnet crystal with data for an undoped garnet. The measurements were carried out in the temperature range from 1.9 to 220 K and in magnetic fields from 0 to 9 T. The temperature dependences of the specific heat were interpreted with allowance for the Schottky contributions due to the Gd^3+ and Er^3+ ions and the contributions of the thermal vibrations of the crystal lattice. The values of entropy and magnetic entropy are calculated.

Cathodoluminescence of Am3+ in zircon, (Zr,Pu,…)SiO4, and garnet, (Y,Gd,…)3(Al,Ga,…)5O12

ABSTRACTCeramic waste forms based on garnet, (Y,Gd,An‥)3(Al,Ga,An‥)5O12, and zircon, (Zr,An‥)SiO4, where An=U, Pu, Np, Am, and Cm have been proposed for the immobilization of weapons-grade plutonium and other actinides. The lattice capacity of these materials depends on the valence state and ionic radius of the substitute ions. The method of cathodoluminescence (CL) allows the determination of the valence state of different ions (e.g., some transition metals, lanthanides, and actinides) in ceramic. There is a lack of information in the literature concerning CL properties of actinide ions. Cathodoluminescence images and emission spectra of synthetic yttrium-aluminum garnet, gallium-gadolinium garnet and zircon doped with Am were studied. Americium ion has three groups of lines of CL in visible region at 1.6eV, 1.9eV and 2.3eV. The interpretation of these lines has been done using the results of absorption spectra of Am in solution and in crystal LaCl3. There are f-f transitions of Am3+ ion. The ratio of intensities and the structure of these lines depend on the matrix. However, the spectral positions of these lines in two types of garnets and in zircon coincide. It was conclude that these lines can be used for identification of Am3+ ion in different crystalline matrices.