Non-Fermi-Liquid Behavior of Superconducting SnH.

The chemical interaction of Sn with H by X-ray diffraction methods at pressures of 180-210 GPa is studied. A previously unknown tetrahydride SnH with a cubic structure (fcc) exhibiting superconducting properties below T  = 72 K is obtained; the formation of a high molecular C2/m-SnH superhydride and several lower hydrides, fcc SnH , and C2-Sn H , is also detected. The temperature dependence of critical current density J (T) in SnH yields the superconducting gap 2Δ(0) = 21.

Effect of Magnetic Impurities on Superconductivity in LaH.

Polyhydrides are a novel class of superconducting materials with extremely high critical parameters, which is very promising for sensor applications. On the other hand, a complete experimental study of the best so far known superconductor, lanthanum superhydride LaH , encounters a serious complication because of the large upper critical magnetic field H (0), exceeding 120-160 T. It is found that partial replacement of La atoms by magnetic Nd atoms results in significant suppression of superconductivity in LaH : each at% of Nd causes a decrease in T by 10-11 K, helping to control the critical parameters of this compound.

Crystal structure of bismuth-containing NdFe(BO) in the temperature range 20-500 K.

Neodymium iron borate NdFe(BO) is an intensively studied multiferroic with high electric polarization values controlled by a magnetic field. It is characterized by a large quadratic magnetoelectric effect, rigidity in the base plane and a rather strong piezoelectric effect. In this work, the atomic structure of (NdBi)Fe(BO) was studied by single-crystal X-ray diffraction in the temperature range 20-500 K (space group R32, Z = 3).

Permeability of the Composite Magnetic Microcapsules Triggered by a Non-Heating Low-Frequency Magnetic Field.

Nanosystems for targeted delivery and remote-controlled release of therapeutic agents has become a top priority in pharmaceutical science and drug development in recent decades. Application of a low frequency magnetic field (LFMF) as an external stimulus opens up opportunities to trigger release of the encapsulated bioactive substances with high locality and penetration ability without heating of biological tissue in vivo. Therefore, the development of novel microencapsulated drug formulations sensitive to LFMF is of paramount importance.

Anomalous High-Temperature Superconductivity in YH.

Pressure-stabilized hydrides are a new rapidly growing class of high-temperature superconductors, which is believed to be described within the conventional phonon-mediated mechanism of coupling. Here, the synthesis of one of the best-known high-T superconductors-yttrium hexahydride -YH is reported, which displays a superconducting transition at ≈224 K at 166 GPa. The extrapolated upper critical magnetic field B (0) of YH is surprisingly high: 116-158 T, which is 2-2.

Flux growth, structure refinement and Mössbauer studies of FeGaBO single crystals.

High-quality FeGaBO single crystals (0.0 ≤ x ≤ 1.0) in the form of basal plates were synthesized by the flux technique.

Crystal structure and structural phase transition in bismuth-containing HoFe(BO) in the temperature range 11-500 K.

An accurate single-crystal X-ray diffraction study of bismuth-containing HoFe(BO) between 11 and 500 K has revealed structural phase transition at T = 365 K. The Bi atoms enter the composition from BiMoO-based flux during crystal growth and significantly affect T. The content of Bi was estimated by two independent methods, establishing the composition as (HoBi)Fe(BO).

Pressure Induced Spin Crossover and Magnetic Properties of Multiferroic BaNbFeSiO.

Recently, the iron containing langasite-type crystal BaNbFeSiO has attracted great attention as a new magnetically induced multiferroic. In this work, magnetic, structural and electronic properties of the multiferroic BaNbFeSiO were investigated by several methods, including synchrotron X-ray diffraction, Raman spectroscopy and synchrotron Mössbauer source technique at high quasi-hydrostatic pressures (up to 70 GPa), created in diamond anvil cells. At room temperature, two structural transitions at pressures of about 3.

Magnetic properties of biofunctionalized iron oxide nanoparticles as magnetic resonance imaging contrast agents.

One of the future applications of magnetic nanoparticles is the development of new iron-oxide-based magnetic resonance imaging (MRI) negative contrast agents, which are intended to improve the results of diagnostics and complement existing Gd-based contrast media. Iron oxide nanoparticles designed for use as MRI contrast media are precisely examined by a variety of methods: powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, Mössbauer spectroscopy and zero-field nuclear magnetic resonance (ZF-NMR) spectroscopy. TEM and XRD measurements reveal a spherical shape of the nanoparticles with an average diameter of 5-8 nm and a cubic spinel-type crystal structure of space group -3.

Mechanism of Transformation of Ferrocene into Carbon-Encapsulated Iron Carbide Nanoparticles at High Pressures and Temperatures.

A mechanism was established for the formation of nanosized iron carbide particles encapsulated in carbon shells via the processes of ferrocene thermal conversions at high pressures. At a pressure of 8.0 GPa, products of ferrocene decomposition were studied as a function of temperature by X-ray diffraction, Raman and Mössbauer spectroscopy, scanning and transmission electron microscopy.

Crystal structure, phase transition and structural deformations in iron borate (YBi)Fe(BO) in the temperature range 90-500 K.

An accurate X-ray diffraction study of (YBi)Fe(BO) single crystals in the temperature range 90-500 K was performed on a laboratory diffractometer and used synchrotron radiation. It was established that the crystal undergoes a diffuse structural phase transition in the temperature range 350-380 K. The complexity of localization of such a transition over temperature was overcome by means of special analysis of systematic extinction reflections by symmetry.

Structural, Magnetic, and Electronic Properties of Mixed Spinel NiFeCrO Nanoparticles Synthesized by Chemical Combustion.

A series of nickel-chromium-ferrite NiFeCrO (with x = 1.25) nanoparticles (NPs) with a cubic spinel structure and with size d ranging from 1.6 to 47.

Observation of superconductivity in hydrogen sulfide from nuclear resonant scattering.

High-temperature superconductivity remains a focus of experimental and theoretical research. Hydrogen sulfide (H2S) has been reported to be superconducting at high pressures and with a high transition temperature. We report on the direct observation of the expulsion of the magnetic field in H2S compressed to 153 gigapascals.

Quantum critical point and spin fluctuations in lower-mantle ferropericlase.

Ferropericlase [(Mg,Fe)O] is one of the most abundant minerals of the earth's lower mantle. The high-spin (HS) to low-spin (LS) transition in the Fe(2+) ions may dramatically alter the physical and chemical properties of (Mg,Fe)O in the deep mantle. To understand the effects of compression on the ground electronic state of iron, electronic and magnetic states of Fe(2+) in (Mg0.

Synthesis, characterization and magnetic properties of nearly monodisperse CuCr2Se4 nanoparticles.

Nearly monodisperse CuCr(2)Se(4) hexagon-shaped nanoparticles with crystallite sizes from 15.1 to 24.3 nm were synthesized by thermal decomposition of metal chlorides and selenium powder in oleylamine.