Low-Temperature Growth of the CdS Cubic Phase by Atomic-Layer Deposition on SiC/Si Hybrid Substrates

Technical Physics Letters - A new method for epitaxial growth of cadmium sulfide (CdS) films in the metastable cubic phase by atomic-layer deposition on silicon substrates with a buffer layer of...     

Microwave-hydrothermal synthesis and characterization of nanostructured copper substituted ZnM2O4 (M = Al, Ga) spinels as precursors for thermally stable Cu catalysts

Nanostructured Cu(x)Zn(1-x)Al(2)O(4) with a Cu:Zn ratio of ?:? has been prepared by a microwave-assisted hydrothermal synthesis at 150 °C and used as a precursor for Cu/ZnO/Al(2)O(3)-based catalysts. The spinel nanoparticles exhibit an average size of approximately 5 nm and a high specific surface area (above 250 m(2) g(-1)). Cu nanoparticles of an average size of 3.3 nm can be formed by reduction of the spinel precursor in hydrogen and the accessible metallic Cu(0) surface area of the reduced catalyst was 8 m(2) g(-1). The catalytic performance of the material in CO(2) hydrogenation and methanol steam reforming was compared with conventionally prepared Cu/ZnO/Al(2)O(3) reference catalysts. The observed lower performance of the spinel-based samples is attributed to a lack of synergetic interaction of the Cu nanoparticles with ZnO due to the incorporation of Zn(2+) in the stable spinel lattice. Despite its lower performance, however, the nanostructured nature of the spinel catalyst was stable after thermal treatment up to 500 °C in contrast to other Cu-based catalysts. Furthermore, a large fraction of the re-oxidized copper migrates back into the spinel upon calcination of the reduced catalyst, thereby enabling a regeneration of sintered catalysts after prolonged usage at high temperatures. Similarly prepared samples with Ga instead of Al exhibit a more crystalline catalyst with a spinel particle size around 20 nm. The slightly decreased Cu(0) surface area of 3.2 m(2) g(-1) due to less copper incorporation is not a significant drawback for the methanol steam reforming.     

Particularities of the photoluminescence spectra of Cr4+:Ca2GeO4 single crystal films

It was found that the room-temperature photoluminescence (PL) spectra of Cr⁴⁺:Ca₂GeO₄ single crystal films grown by magnetron sputtering on Ca₂GeO₄ bulk single crystal substrates exhibit a sharp emission band in the region of ～1.17 μm with satellites at ～1.21 and 1.27 μm. Particularities of the PL spectra are interpreted within the framework of a model based on the interaction between electrons of the Cr⁴⁺ center and the oscillations excited in the film.     

Magnetic Random Access Memory Devices

New types of prospective magnetic random access memory devices are reviewed. Operation principles, design, characteristics, and the state-of-the-art of magnetoresistive, microelectronic electrical, and quantum-optical devices are described.     

Analysis of geological samples for gold and silver by the method of spectral ratios

Translated from Atomnaya Énergiya, Vol. 66, No. 1, pp. 42–44, January, 1989.     

Failure resistance in static loading of steels with σ0.2 > 600 MPa and their welded joints

Investigations were carried out into the failure resistance in the temperature range +20 to –60°C in static bending of 13KhGMRB, 14KhG2SAFD, and 14KhGN2MDAFB steels with _0.2=600–700 MPa and also the weld metal and the heat affected zone (HAZ) of their welded joints. Evaluation of the cracking resistance of these steels and welded joints was carried out using fracture mechanics criteria: critical crack opening displacement _c and stress intensity factor K_c. The values of the effective factor of stress concentration, generated by the crack {ie746-01}, and critical stress _cr are also determined. The results show that of the three steels tested, the lowest failure resistance was exhibited by 14KhGN2MDAFB steel. The heat affected zones of the welded joints in the 13KhGMRB and 14KhGM2MDAFB steels have higher cracking resistance than the HAZ of the welded joints in 14KhG2SADF steel. The weld metal of welded joints produced in CO₂ with PP-AN54 wire and in a Ar+CO₂ mixture with Sv-08KhN2GNYu wire is characterized by higher failure resistance than the weld metal of welded joints produced in CO₂ with Sv-10KhG2SMA wire. The welded joints in 13KhGMRB steel produced in CO₂ with PP-AN54 wire, and in 14KhGN2MDAFB steel produced in the Ar+CO₂ mixture, have high failure resistance at temperatures to –60 and –50°C, respectively. The welded joints in 14KhG2SAFD steel, produced in CO₂ with Sv-10KhGSMA wire, can be used in service at temperatures not lower than –40°C.Translated from Problemy Prochnosti, No. 7, pp. 30–34, July, 1991.     

Study of Spin-Tunnel Junction Magnetization Using Coherent Rotation of the Free Layer Magnetization Model

Russian Microelectronics - The influence of a magnetic field directed orthogonal to the easy magnetization axis (EMA) of an elliptical spin-tunnel junction based on the...