Temperature Evolution of the Dielectric Response of α-Lactose Monohydrate in the THz Frequency Range

Optics and Spectroscopy - Transmission spectra of pressed microcrystalline α-lactose monohydrate samples have been measured by THz time-domain spectroscopy in the temperature range of...     

Dielectric Loss of Thin-Film SiO2 Samples on Al in THz–IR Range

Physics of the Solid State - The development of new dielectric materials for insulating layer of interconnects with low loss on high frequencies (low-k) is one of main directions of modern...     

Structure of the mixed state induced in thin YBaCuO superconducting films by the field of a small ferromagnetic particle

The temperature dependence of the local energy barrier to formation of the mixed state in YBaCuO thin-film superconducting samples has been determined. The measurement technique is based on use of a small ferromagnetic particle as the magnetic field source. It is found that the energy barrier to creation of vortices (for the field oriented parallel to the CuO planes) is anomalously small while the dependence of the corresponding threshold current j _c(T) differs substantially from the temperature dependence of the pair-breaking current. The experimental results are interpreted in terms of the model of a Josephson medium. The observed temperature dependence of j _c points to a strong suppression of the superconducting order parameter at the intergrain boundaries, which for the most probable type of boundaries: superconductor-insulator-superconductor, is evidence of anisotropic pairing. Zh. éksp. Teor. Fiz. 116, 1735–1749 (November 1999)     

Study of the structure of a superconducting state of Co-doped BaFe2As2 multiband compounds

The terahertz and infrared spectra of the complex dynamic conductivity, as well as the temperature dependences of the density of a superconducting condensate and the electronic specific heat of superconducting Ba(Fe_{1 ? x} Co _x )₂As₂ compounds, have been analyzed within a Bardeen-Cooper-Schrieffer-like model of a multiband superconductor with strong coupling. It has been shown that the superconducting state of these compounds is determined by three (one electronic and two hole) weakly interacting condensates. The order parameters of the condensates are: Δ₁ ≈ 15 cm^?1, Δ₂ ≈ 21 cm^?1, and Δ₃ ≈ 30–35 cm^?1. The results significantly refine the existing notions on the structure of the superconducting state of Co-doped BaFe₂As₂ multiband compounds.     

Effect of thermal annealing on the magnetic properties of thin films of Co-Pd alloys

The results of studies of the effect of thermal annealing on the magnetic properties of thin films of Co-Pd alloys are described, along with a method for obtaining easy-axis perpendicular anisotropy in these materials. The method consists of depositing layers of the alloy on a substrate whose thermal expansion coefficient is considerably smaller than that of the film, and then annealing it in a vacuum. This method is used to prepare samples with rectangular hysteresis loops for magnetization perpendicular to the plane of the film, coercive forces of 750 Oe, and Kerr rotation angles of 0.21°. Also presented are the results of experiments on thermomagnetic recording on the samples. Zh. Tekh. Fiz. 68, 66–70 (April 1998)     

Terahertz and Infrared Spectroscopy of Dense and Porous Organosilicate Glass Thin Films

Doklady Physics - Wide-range measurements of thin films of SiCxOyHz organosilicate glasses, both dense and porous, deposited on dielectric sapphire substrates and conductive layers of platinum and...     

Electrodynamical Characteristics of α-Lactose Monohydrate in the Terahertz Range

Optics and Spectroscopy - Using methods of infrared, terahertz, and submillimeter spectroscopy, experimental transmission and reflection spectra of α-lactose monohydrate have been obtained at...     

Collective effects accompanying magnetization of two-dimensional lattices of nanosize magnetic particles

Collective effects arising in a two-dimensional lattice of nanosize magnetic particles as a result of the dipole interparticle interaction are investigated by Hall magnetometry. The experimental system consists of 10⁵ permalloy particles having a diameter of ∼40 nm and a height of ∼40 nm and forming a lattice with a rectangular unit cell (90 nm×180 nm). We attribute the characteristic features observed in the magnetization curves to quasi-one-dimensionality of the experimental lattice of particles and to the formation of solitons in chains of dipoles. Pis’ma Zh. éksp. Teor. Fiz. 68, No. 6, 475–479 (25 September 1998)