Electrical and structural parameters of YBCO films obtained by repeated growth cycles

We have studied changes in the electrical and structural characteristics of YBa₂Cu₃O_{7 − δ} (YBCO) films in the course of step-by-step increase in their thicknesses up to about 1 μm in a series of repeated magnetron sputtering growth cycles. It is established that high quality of the films is not deteriorated by interrupts in the growth process, which involve the formation of patterns on the sample and measurement of its electrical properties in liquid nitrogen. These results show the possibility of introducing intermediate stages of lithography into the process of YBCO deposition for the formation of structures with nonuniform thicknesses.     

The relaxation of the neutral state of manganese in gallium arsenide

Results of investigations of the longitudinal magnetic relaxation of the neutral state of the Mn⁰ center in GaAs are presented. Relaxation mechanisms were determined from the broadening of the electron-spinresonance line in the temperature range of 3.4–8.2 K and from the variation in the nuclear relaxation rate in the range of 36–310 K. The nuclear relaxation investigation demonstrates that the electron relaxation is governed by the interaction between lattice vibrations and local vibrations of the center. This allows one to represent the electron relaxation at low temperatures as the consequence of anharmonicity of local vibrations of the electron dipole moment of the Mn⁰ center.     

The role of apitherapy in the combined treatment of patients with chronic nonspecific lung diseases]

The authors suggest that apitherapy should be used in the treatment of patients with chronic non-specific pulmonary diseases (ChNPD) in order that it might be more effective. Apitherapeutic complex (bee venom and bee keeping apiculture produce) has been applied to the treatment of 104 ChNPD patients. High effectiveness of apitherapy in a combined treatment of ChNPD patients was demonstrated as was their stimulating and normalizing influence on the function of the adrenals.     

Characteristics of neutron and gamma radiation in the core of the ΦC-1-4.37.P critical assembly

The characteristics of neutron and γ-ray fields (spectrum, flux density, average energy, cross sections of 23 nuclear reactions, and γ-ray dose rate) and the γ-ray field in the core of the ΦC-1-4.37.P critical assembly of the ΦC-1M critical bench are determined. The results of comparing the characteristics of the neutron fields of the ΦC-1-4.37.P critical assembly and analogous reactors are presented.     

Royleanones in the roots of Salvia officinalis L. of domestic provenance and their antimicrobial activity

The reported investigation of the constituents of the petroleum ether extract of the root of Salvia officinalis L. confirmed the presence of the following diterpene quinones: 12.hydroxy-8, 12-abietadiene-11, 14-dione (royleanone), 7 alpha, 12-dihydroxy-8.12-abistadiene-11-14-dione (horminone) and 7 alpha-acetoxy-12-hydroxy-8, 12-abietadiene-11,14-dione (7-O-acetylhorminone). The compounds were identified on the basic of the interpretation of results of spectral analysis. Isolated royleanones show antimicrobial activity against gram-positive bacteria (Staphylococcus aureus). A study of abietate diterpenoids in the root of Salvia officinalis L. of Slovak provenance has been performed for the first time.     

Electronic structure of the Er-O6 complex in silicon

The energy diagram of the Er-O₆ complex in silicon is calculated. The square amplitudes of the wave functions of the complex on the erbium atom are determined. The results of our calculations show that the Er-O₆ complex is an acceptor in silicon. In addition, it is possible that the electron trap energy level is located in the energy gap of silicon. On the whole, the results of our calculations correspond to the Er-O quantum dot model proposed previously. Fiz. Tekh. Poluprovodn. 31, 1037–1044 (September 1997)     

Features of technology of high-temperature superconductor films for microwave filters

The characteristics of fourth-order bandpass microwave filters based on high-temperature super-conductor (HTS) films have been numerically simulated and experimentally measured for the devices based on YBCO films purchased from Theva GmbH (Munich) and manufactured at the Institute for Physics of Microstructures (Nizhni Novgorod). Experimental data were used to determine the parameters of the surface impedance model for the HTS films. The results show that HTS-based filters with high performance characteristics can be obtained using HTS films manufactured by different technologies.     

Hubbard energy of two-electron tin centers in PbS1−zTez solid solutions

It is shown by Mössbauer spectroscopy of the isotope ¹¹⁹Sn that an isovalent tin impurity in PbS_1?z Te_z solid solutions is a two-electron donor with a negative correlation energy, where the energy levels associated with tin centers are situated against the background of the valence band continuum. The Hubbard energy U is estimated for impurity tin atoms in PbS_1?z Te_z (|U|>0.2 eV), which is found to be substantially higher than for analogous tin centers in PbS_1?z Se_z solid solutions (|U|=0.058 eV).     

Gas-sensitive properties of copper-containing fullerene membranes

The gas-sensitive properties of copper-doped polycrystalline fullerene members are studied in the temperature range 280–360 K. The presence of isopropanol vapor in the surrounding air is found to increase the microwave absorption of the samples examined. The sensitivity of the samples is temperature-selective and depends on the relative orientation of the crystals, as well as the vector of the electric component of the electromagnetic microwave field. Pis’ma Zh. Tekh. Fiz. 25, 71–75 (April 26, 1999)     

The Metal-Insulator Transition and Superconductivity in Allotropes of Carbon Intercalated with Copper: Prediction and Experiment

The complex of studies carried out on Cu_nC₆₀ samples, including SQUID and microwave measurements clearly support the existence of a superconducting phase of Cu_1,5 C₆₀ with T_c=120K. Heating a samples of pyrolitic graphite intercalated with copper and oxygen above 77K initiates a Metal - Insulator transition. We assume the same idea that the superconducting transition temperature T_c in Cu_n C₆₀ samples changes near the M -I transition.