Electrodeposited Co–Ni Films: Electrolyte pH—Property Relationships

The effect of electrolyte pH on structural, magnetic, and magnetoresistive properties of Co–Ni films was studied. The films were deposited on a titanium substrate from the electrolytes with 4.10±0.05, 3.14±0.05, and 2.14±0.05 pH values. The Co–Ni system exhibited anomalous codeposition. Structural analysis indicated that the films had (220) preferential oriented face-centered cubic structure and their surface became smoother as the electrolyte pH decreased. The compositional and magnetic analysis revealed that an increase of the Co content in the films resulted in an increase in saturation magnetization and coercivity. Magnetoresistance curves indicated that the films show anisotropic magnetoresistance. Longitudinal and transversal magnetoresistances were found to be the highest values of 8 % and 7 %, respectively, for the film deposited at a low electrolyte pH. The variation of the Co:Ni ratio in deposits caused by the change of the electrolyte pH has a considerable effect on the properties of the films.     

Formation of Highly Conducting Optically Transparent Films with Multigraphene Structure via Carbonization of Polyimide Langmuir–Blodgett Films

Technical Physics Letters - Multigraphene films have been for the first time obtained on the surface of quartz glass via carbonization of polyimide Langmuir–Blodgett films. The Raman spectra...     

Moiré Superlattice Structure in Two-Dimensional Catalysts: Synthesis,Property and Activity

Two-dimensional (2D) layered materials have been widely used as catalysts due to their high specific surface area, large fraction of uncoordinated surface atoms, and high charge carrier mobility. Moiré superlattice emerges in 2D layered materials with twist angle or lattice mismatch. By manipulating the moiré superlattice structure, 2D layered materials present modulated electronic band structure, topological edge states, and unconventional superconductivity which are tightly associated with the performance of catalysts. Hence, engineering moiré superlattice structures are proposed to be an important technology in modifying 2D layered materials for improved catalytic properties. However, currently, the investigation of moiré superlattice structure in a catalytic application is still in its infancy. This perspective starts with the discussion of structural features and fabrication strategy of 2D materials with moiré superlattice structure. Afterward, the catalytic applications, including electrocatalytic and photocatalytic applications, are summarized. In particular, the promotion mechanism of the catalytic performance caused by the moiré superlattice structure is proposed. Finally, the perspective is concluded by outlining the remaining challenges and possible solutions for the future development of 2D materials with moiré superlattice structure towards the catalytic applications.     

The Influence of the Interface on the Magnetic State in Two-Layer Films of the Fe–Bi System

Technical Physics Letters - Results of the experimental investigation of two-layer films in the Fe–Bi system are presented. It is found that the order of sequential deposition of the magnetic...     

Solid-State Reactions in CdS–Bi2S3 Thin Films

Structural, electrical, and optical data are used to elucidate the mechanisms of solid-state reactions in thin CdS–Bi₂S₃ films prepared by spray pyrolysis. The results indicate the formation of substitutional solid solutions and a chemical compound and intercalation of Cd between layers of Bi₂S₃.     

Structure of metastable precipitate in some Al–Cu–Mg–Ag alloys

Abstract

The high strength of some Al–Cu–Mg–Ag alloys has been attributed to very thin (~2·5 nm), but broad, hexagonal-shaped precipitates. Previous work has shown that the precipitates have a hexagonal unit cell, but different lattice parameters have been reported. In the present paper, the intensities of X-ray diffraction reflections from the precipitates have been measured on Buerger precession photographs, and it is shown that the crystal structure is monoclinic (space group P2/m) with the parameters a = b = 0·496 nm, c = 0·848 nm, γ = 120°. The special values of these parameters confer a hexagonal symmetry on the lattice. This unusual structure is a slightly distorted form of θ-CuAl₂, to which it appears to change after long aging times at 200°C.     

The Fulde–Ferrell–Larkin–Ovchinnikov State in Pnictides

We present experimental results on crosstalk of non-electrical origin between high frequency quartz tuning forks immersed in the same volume of helium gas, liquid or superfluid. We compare these results with various observations of other groups and propose an explanation of this puzzling phenomenon. To the best of our knowledge, notable crosstalk has only been observed in superfluid helium both in the two-fluid regime and at very low temperatures, but was rarely seen to behave in a systematic way. We demonstrate some of its most significant properties—amplitude dependence within a short time span, long-term temporal instability, effects of the geometry of the setup and of obstacles placed between the tuning forks. Although the results are not fully understood, as the most likely explanation, we ascribe the observations to the coupling of tuning forks to standing acoustic modes inside the experimental volume, emphasizing the importance of second sound for understanding the observations at temperatures within the two-fluid regime (1 K<T<2.17 K). Finally, we suggest simple precautions leading to suppression of excessive acoustic crosstalk between oscillating objects in He II.     

The First Property Management Quality Standard Takes the Lead in Qingdao Service Market

City residentspay the propertymanagement feesevery month , but what and atwhat levelshould the proper-ty companies manage afterthey receivethe fees? Which lacksa cleardefinition. Recently Qingdao Bureau ofQualityand Technical Supervisionof Shandong Province issued“Qingdao PropertyManagement ServiceQuali-ty Requirements”. Itissaidthisisthe firststandardforpropertyservicein our country, and ittook effectonFebruary 1.　　　In thislocalrecommendatory standard, the servicesof the propertyco…     

Structural Changes in Si–CuSi Films upon Intercalation of Lithium Ions

Technical Physics Letters - We studied the possibility of using composite films representing amorphous silicon reinforced with crystalline inclusions of copper silicide as an anode material for...     

Peculiarities of the Structure and Properties of Thin PZT Films with Strongly Nonuniform Depth–Composition Profiles

Technical Physics Letters - Two-layer thin films of lead zirconate titanate (PZT) with lead content in the layers differing by 20% were deposited by RF magnetron sputtering at variable working gas...     

The magnetoelectric effect in nickel–GaAs–nickel structures

Technical Physics Letters - We have experimentally studied the magnetoelectric (ME) effect in structures obtained by the electrolytic deposition of nickel onto gallium arsenide substrates. It is...     

Control of Microstructure in Iron–Carbon Thin Films by Means of Electromigration

Herein, it is demonstrated that high DC electric current densities can be used to tailor the microstructure of iron–carbon thin films. Specifically, elongated ferrite grains can be formed in a nanocrystalline matrix via a process involving electromigration-induced carbide migration. Herein this article, the parameters that are required to produce and control elongated grain formation in the Fe(C) system are mapped out and they are interpreted in terms of carbon electromigration, and the flux divergences need to reach a critical carbon concentration for precipitate growth and migration. Possible approaches to allow more precise control of the elongated grains are discussed, as are the requirements for material systems where microstructure control through electromigration should be feasible.     

Dry separation of particulate iron ore using density-segregation in a gas–solid fluidized bed

A gas–solid fluidized bed has been used to separate particulate iron ore (+250–500 μm in size) by segregating the particles by density. The ore particles were put into a cylindrical column of inner diameter of 100 mm and bed height of 50 mm, and were fluidized at a given air velocity u₀/u_mf = 1.2–3.2 for 10 min. u₀ and u_mf are the superficial air velocity and the minimum fluidization air velocity, respectively. The bulk density of the ore particles after fluidization was measured as a function of height through the bed in 5 mm increments (the 50 mm height was divided into 10 layers) to investigate the density-segregation. The size of the particles in each of the 10 layers was also measured to investigate size-segregation. It was found that both density-segregation and size-segregation occurred as a function of height through the bed after fluidization at u₀/u_mf = 2.0. However, the segregation did not occur near the bottom of the bed for lower u₀/u_mf and did not occur near the top of the bed for larger u₀/u_mf. The origin of the segregation-dependence on the air velocity was discussed considering the air bubbles size and the fluidizing intensity at upper and lower sections of the bed. The Fe content of the 10 layers at u₀/u_mf = 2.0 was measured to calculate the Fe-grade and Fe-recovery. The ore-recovery was also calculated using the weight of ore particles as a function of height through the bed. The feed Fe-grade (before separation) was 52.1 wt%. If the ore particles in the bottom half of the bed were regarded as the product, the Fe-grade was 59.0 wt%, and the Fe-recovery and the ore-recovery were 68.5 wt% and 60.5 wt%, respectively.     

Parametric Amplification of Magnetoacoustic Oscillations in a Ferromagnet–Piezoelectric Structure

Technical Physics Letters - A parametric amplification of magnetoacoustic oscillations in a disk resonator containing a FeBSiC ferromagnetic layer and a lead zirconate–titanate piezoelectric...     

Structure engineering in vacuum-arc-deposited coatings of the MoN–CrN system

Technical Physics Letters - The possibilities of structure engineering in multilayer coatings of the MoN–CrN system with relatively low heats of formation of component transition metal...     

Planar Structure Optimization of Extraordinary Magnetoresistance in Semiconductor–Metal Hybrids

The performance of extraordinary magnetoresistance (EMR) depends on the material parameters, hybrid structure design, contacts configuration, and manufacturing technology. In this paper, we pay close attention to the hybrid structure of the EMR device. A semiconductor–metal hybrid model based on the finite element method (FEM) is constructed to study the EMR effect, and the results show good agreement with the experimental data. The analysis of the van der Pauw plate structure indicates that the relationship between the two voltage probe contacts and the different EMR structures is the key factor to the design optimization. Accordingly, we find that the elliptic inclusion configurations improve the performance of the van der Pauw structure of EMR devices within a wide range of applied magnetic field (0–5 T). The bar-type and multibranched inclusion structures are subsequently optimized based on this principle. The new structures show excellent performance; more specifically, the modified multibranched inclusion structure displays a 2-fold increase in the magnetoresistance at 0.1 T and more than 2-order-of-magnitude increase at 5 T when compared with the original structure.     

Anomalous Domain Wall Magnetoresistance in Ultrathin Manganite Films Near M–I Transition Boundary

Resistance and magnetoresistance in compressively strained epitaxial ultrathin films have been studied. The samples were first demagnetized in different ways so that different magnetic structures were created, such as random domain and single domain states. Very large difference in resistance in zero applied magnetic field was observed between different states. The large change of resistance between states is attributed to spin-dependent scattering at the domain walls. We have shown for the first time that large domain wall resistance can be obtained in strained ultrathin manganite films and the result cannot be explained by the double-exchange model.     

Mechanochemical Synthesis and Structure of New Phases in the Pb–V–O System

The products of mechanochemical synthesis in the Pb–V–O system were characterized by x-ray diffraction and magnetic resonance spectroscopy techniques. The mechanical processing was found to yield only new crystalline compounds, Pb_2.67V_1.33O_5.96and Pb_3.5V_4.5O_14.75. Structural analysis of these phases revealed a low atomic density, mixed-valent states of the constituent cations, the presence of three of four types of vanadium polyhedra, and splitting of crystallographic sites, in line with the views on the mechanisms of mechanochemical reactions developed in the model for the reaction zone.