Structure and Lattice Dynamics of R $$_2$$ 2 Sn $$_2$$ 2 O $$_7$$ 7 and R $$_2$$ 2 Zr $$_2$$ 2 O $$_7$$ 7 (R = La–Lu) Crystals: Ab Initio Calculation

Journal of Superconductivity and Novel Magnetism - Crystal structure and phonon spectrum of rare-earth stannates R $$_2$$ Sn $$_2$$ O $$_7$$ and zirconates R $$_2$$ Zr $$_2$$ O $$_7$$ (R =...     

Synthesis and Magnetic Properties of TNb $$_3$$ S $$_6$$ (T = Co,Ni, Cu)

Journal of Superconductivity and Novel Magnetism - We have studied the magnetic properties of transition metal intercalated niobium dichalcogenides CoNb $$_3$$ S $$_6$$ , NiNb $$_3$$ S $$_6$$ and...     

Electronic and Magnetic Properties of the BaTiO $$_{3}$$ 3 /LaMnO $$_{3}$$ 3 Interface: a DFT Study

Journal of Superconductivity and Novel Magnetism - The electronic and magnetic properties of the BaTiO $$_{3}$$ /LaMnO $$_{3}$$ interface were investigated by means of ab initio calculations within...     

Physical Properties of Antiferromagnetic Dirac Semimetal SrMnSb $$_{2}$$

Journal of Superconductivity and Novel Magnetism - We have prepared high-quality nearly stoichiometric single crystal of Dirac semimetal SrMnSb $$_{2}$$ and systematically investigated the physical...     

Preparation and electrical properties of sintered oxides composed of Mn1.5Co(0.25+X)Ni(1.25-X)O4 ( $$0 \leqq X \leqq 0.75$$) with a cubic spinel structure

Monophase cubic spinel-type oxides of Mn_1.5Co_(0.25+X)Ni_(1.25-X)O₄ ( ) were prepared through the oxidation of specimens sintered at 1400 °C. The oxides with composition are focused on in this study, as the oxides with composition did not convert into a monophase cubic spinel structure. The electrical conductivity of the sintered bodies was confirmed to increase exponentially with increasing temperature. In the composition range of , both the electrical conductivity and the Seebeck coefficient increased with increasing X. The oxides with composition between were n-type semiconductors, whereas those with were p-type. It was concluded that electrical conduction in the specimens is controlled by small polaron hopping.     

First-principles Investigations on the Magnetic,Electronic, and Optical Properties of Honeycomb-Kagome-Structured Fe $$_{2}$$ O $$_3$$ Monolayer

Journal of Superconductivity and Novel Magnetism - Two-dimensional materials with a novel honeycomb-kagome structure have got a variety of attentions owing to their dramatic properties. In the...     

The Magnetic Properties of Different Proportions Cr-Doped Bifeo3 as Studied Using Heisenberg Model

Journal of Superconductivity and Novel Magnetism - With the Monte Carlo method, we simulate 3D alloys Heisenberg model of Cr-doped BiFeO $$_3$$ with various proportions Cr-doped. This model...     

X-Ray Diffraction Study of Correlated Electron System at Low Temperatures

By using an ultra-low temperature X-ray diffractometer, we studied low temperature phase transitions of several materials. These phase transitions are classified into a ferro quadrupole ordered phase, that is, Jahn–Teller distortion (TmVO, ZnCrO), an antiferro quadrupole ordered phase (CeB, PrPb), and a superconducrivity (MgB). We also investigated unknown phases, such as the low temperature phase in PrPtBi and the 4th phase in CeLaB. Our low temperature X-ray measurement gives rise to a fruitful information about the phase transition. Not only a whole profile of the reflection peaks, which can be analyzed by the Rietveld method, we also made the precise measurement of the temperature dependence of the integrated intensity of the reflection peak, the full width at half maximum, and the lattice spacing for some fixed reflections. The temperature dependence of the integrated intensity (I.I.) can be expressed by the Debye–Waller expression. At low temperatures, the change of the phonon frequency can be obtained from the I.I. through the Debye–Waller factor. In MgB we observed the hardening of the phonon and the softening of phonon above and below the superconducting transition temperature, respsctively. This result suggests the relevant mechanisim of superconductivity in MgB is the electron–phonon interaction. From the precise measurement of the lattice constant, we found the negative thermal expansion at low temperatures in many correlated electron system. This negative thermal expansion can be explained by the Fermi liquid theory by Misawa.     

Identify the Nematic Superconductivity of Topological Superconductor Pd $$_x$$ x Bi $$_2$$ 2 Te $$_3$$ 3 by Angle-dependent Upper Critical Field Measurement

Journal of Superconductivity and Novel Magnetism - Odd-parity superconductivity is recognized as a key ingredient to realize topological superconductivity. In Bi2Se3-based bulk topological...     

Two-Band Eliashberg Theory in Doped MgB $_{2}$_{2}: Experimental Tc and Superconductive Gaps

The variation of the critical temperature and of the superconductive gaps as functions of doping (Al, C) in the diboride MgB has been studied in the framework of the two-band Eliashberg theory and traditional phonon coupling mechanism. We have solved the two-band Eliashberg equations using first-principle calculations or simple assumptions for the variation of the relevant physical quantities. We have found that the experimental curves can be exactly explained only if the Coulomb pseudopotential changes with x by tuning the Fermi level toward the σ band edge. We also found that a small amount of impurities changes the structural properties of the material, so we cannot treat the Mg and MgB systems as a contamination with Al or C of MgB, but as new materials. Finally, we compare the predictions of our theory with the available experimental data.     

Epitaxy of GaN(0001) and GaN(10 $$\bar {1}$$ 1) Layers on Si(100) Substrate

Technical Physics Letters - Two different approaches to epitaxy of 4-μm-thick layers of polar GaN(0001) and semipolar GaN(10 $$\bar {1}$$ 1) on a V-shaped nanostructured Si(100) substrate with...     

Study of Cuprate Superconductivity Using the Particle Number Conserving Bogoliubov-de Gennes Equations: ARPES and STS Images From Surface Plus Bulk Layers Model

Journal of Superconductivity and Novel Magnetism - We theoretically study the superconductivity in hole-doped cuprate superconductors by employing a model composed of surface and bulk CuO $$_2$$...     

Hydrothermal Synthesis of Single-Domain Zinc Ferrite Nanoparticles ( $$\mathrm {ZnFe_{2}O_{4}}$$ ZnFe 2 O 4 ): Structural,Morphological, and Magnetic Studies

Journal of Superconductivity and Novel Magnetism - In order to investigate the size dependence of magnetic properties in the single-domain and superparamagnetic regimes, zinc ferrite $$\mathrm...     

Coexistence of Quasi-One- and -Two-Dimensional Electronic Structures in (EDO-TTF)2X (X = GaCl4, ReO4)

Crystal structures and physical properties of (EDO-TTF)₂X where EDO-TTF = ethylenedioxytetrathiafulvalene, X = GaCl₄ and ReO₄ were investigated. These isostructural salts belonged to triclinic system with space group P1, and two kinds of the donor layers coexisted in a crystal. EDO-TTF formed head-to-tail and head-to-head type columnar structures in each donor layer, for which quasi-one- and -two- dimensional Fermi surfaces were calculated, respectively.     

Lead-strontium titanate glass ceramics: I – crystallization and microstructure

The crystallization behaviour of glasses in the system [(Pb Sr ) O·TiO₂]-[2SiO₂· B₂O₃]-[K₂O]-[BaO] (0.2 ≤ x ≤ 0.9) have been studied. Perovskite titanate was found to be the major phase in all the glass ceramic samples investigated. The actual composition of crystalline phases could not be confirmed on the basis of shift in the X-ray diffraction (XRD) peak positions because of similar effects due to solid solution formation and strain due to crystal clamping. Comparison of the observed intensities of various XRD peaks of the perovskite titanate phase with the calculated intensities for (Pb Sr )TiO₃ with same lead/strontium ratio confirmed the formation of lead strontium titanate solid solution. Microstructural characteristics of various glass ceramics are also discussed. The advantages of using K₂O and BaO as additives instead of only K₂O are also discussed.     

Electrochemical fabrication of (TMTSF)2X (X = PF6, BF4, CIO4) nanowires

TMTSF-based (TMTSF = tetramethyltetraselenafulvalene = C10H12Se4) charge-transfer salt nanowires were fabricated using the galvanostatic deposition technique that was assisted by an anodic aluminum oxide (AAO) template. By applying a low current density of 1-2 microA/cm2 for more than one month, nanowire arrays with diameters of approximately 150 nm and lengths of approximately 6 microm were obtained. The length of nanowires can be controlled by the duration of the constant current application. Energy-dispersive X-ray spectroscopic (EDX) analysis confirmed that selenium is one of the main components of the nanowires. The micro-Raman (v3C == C) and FT-IR spectra (v3PF6-, v3BF4-, v3CIO4-) indicated that the nanowire arrays had the (TMTSF)2X (X = PF6, BF4, CIO4) phase. The TEM images and the selected area electron diffraction (SAED) patterns indicate that the nanowires were not single crystals, but the current-voltage characteristic that was measured with the four-terminal method showed the conductivity of the (TMTSF)2PF6 single crystals (sigmaRT = 1.6 S/cm) at room temperature.     

First Principle Calculations and Monte Carlo Simulations Investigation of Structural,Electronic, Magnetic,Elastic and Thermoelectric Properties of Antiperovskites $$Mn_3ZnX (\mathrm{X}= \mathrm{C, \ N})$$ M n 3 Z n X ( X = C,N )

Journal of Superconductivity and Novel Magnetism - The structural, electronic, magnetic elastic and thermoelectric properties of $$Mn_3ZnX$$ (X = N,C) have been investigated in the framework of...     

0D Cs3Cu2X5 (X = I,Br, and Cl) Nanocrystals: Colloidal Syntheses and Optical Properties

0D lead‐free metal halide nanocrystals (NCs) are an emerging class of materials with intriguing optical properties. Herein, colloidal synthetic routes are presented for the production of 0D Cs₃Cu₂X₅ (X = I, Br, and Cl) NCs with orthorhombic structure and well‐defined morphologies. All these Cs₃Cu₂X₅ NCs exhibit broadband blue‐green photoluminescence (PL) emissions in the range of 445–527 nm with large Stokes shifts, which are attributed to their intrinsic self‐trapped exciton (STE) emission characteristics. The high PL quantum yield of 48.7% is obtained from Cs₃Cu₂Cl₅ NCs, while Cs₃Cu₂I₅ NCs exhibit considerable air stability over 45 days. Intriguingly, as X is changed from I to Br and Cl, Cs₃Cu₂X₅ NCs exhibit a continuous redshift of emission peaks, which is contrary to the blueshift in CsPbX₃ perovskite NCs.     

Near-infrared combination and overtone bands of the CH2 sequence in CH2X2, CH2XCHX2, and CH3(CH2)5CH3 and their characteristic frequency zones

We characterized near-infrared spectra of the CH2 sequence in CH2X2 (X=halogen), CH2ClCHCl2, and CH3(CH2)5CH3. Each near-infrared absorption in the region from 3500 to 10,000 cm-1 is consistently assigned to one of the five different combination or overtone groups, in the order of increasing frequency, of the {[v(CH)]+[delta(CH)]} (A), {[v(CH)]+[2delta(CH)]} (B), [2v(CH)] (C), {[2v(CH)]+[delta(CH)]} (D), and [3v(CH)] (E) types, where v(CH) and delta(CH) denote the CH stretching and CH deformation normal modes, respectively. Each group has its own characteristic frequency zone. The bands of B, D, and E, which are second-order combinations or overtones, are weaker by 1/10-1/50 than those of A and C, which are first-order combinations or overtones. The near-infrared spectra of the CH2 sequence show "window zones" of very weak or no absorptions. This suggests that we can perceive the characteristic near-infrared bands of a functional group through the window zones, and we give an example to demonstrate this. The first-order combination bands of type A only of CH2X2 are reasonably assigned to a pair of the normal modes of v(CH) and delta(CH). From this we predict that the first-order combination bands should give structural information on the CH2 chain, similar to the infrared fundamental bands.     

Phase Equilibria in the Ternary Reciprocal System K+, Ba2+||Br–, $${\text{MoO}}_{4}^{{2 - }}$$

Inorganic Materials - The ternary reciprocal system K+, Ba2+||Br–, $${\text{MoO}}_{4}^{{2 - }}$$ has been divided into stable simplexes by a thermodynamic method, stable sections have been...