The Study of Anisotropy and Domain Condition of Permalloy Thin Films

Hysteretic Loops, 1,5; 3,0; 4,5; 6 and 10 nm in thickness, obtained by magnetron sputtering of Ni81Fe19 alloy, were measured by means of vibration magnetometer. It has been detected that by increasing the film thickness from 3 to 10 nm coercive force (HC) increases as well. In the direction perpendicular to the axis of easy magnetization the loop form considerably differs from the right-angled one, which is caused by amplitude dispersion of anisotropy. The films, derived in scattered magnetic field of the Earth, are by magnetic parameter isotropic. The results of atomic force microscope investigation indicate to the granular structure of films and confirms the presence of non-magnetized areas among the examined films. The critical thickness at which permalloy films pass from multi-domain to single-domain state was 10 nm. Estimation of the critical thickness of the transition from single-domain state to superparamagnetic led to the values of 1.5-2 nm. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3362

Experience of creation and application of automatic meteorological stations in polar regions

The article deals with the development of automated technologies for observing the weather in the polar regions with the help of automatic autonomous meteorological stations. The experience of using the best domestic and foreign samples of this equipment is analyzed, ways of its improvement and development of the observation network are determined

Reconstruction of three-dimensional surface structure of hard-to-reach objects using prism-based stereoscopic systems

Video endoscopes with stereoscopic prism-based optical systems are widely used for non-destructive testing and geometric measurements of hard-to-reach elements inside complex technical objects. The functionality of the existing devices of this type is limited to a great extent by the capabilities of the embedded software. In this paper, we present our software for the calibration of such systems and the processing of obtained stereoscopic images. It allows to reconstruct and process the whole array of three-dimensional coordinates of the observable object points, to compare it with the reference surfaces and to export the data to other mathematical software.The reported study was funded by RFBR according to the research project № 17-29-03469

Subcarrier Wave Quantum Key Distribution in Telecommunication Network with Bitrate 800 kbit/s

In the course of work on creating the first quantum communication network in Russia we demonstrated quantum key distribution in metropolitan optical network infrastructure. A single-pass subcarrier wave quantum cryptography scheme was used in the experiments. BB84 protocol with strong reference was chosen for performing key distribution. The registered sifted key rate in an optical cable with 1.5 dB loss was 800 Kbit/s. Signal visibility exceeded 98%, and quantum bit error rate value was 1%. The achieved result is a record for this type of systems

Investigation of resistance formation mechanisms for contacts to n-AlN and n-GaN with a high dislocation density

We studied temperature dependences of the resistivity, Pc(T) , of Pd-Ti-Pd-Au ohmic contacts to wide-gap semiconductors n - GaN and n - AlN with a high dislocation density. BothPc(T) curves have portions of exponential decrease, as well as those with very slight Pc(T) dependence at higher temperatures. Besides, the Au-Pd-TiPd-n-GaN contacts have a portion of Pc(T) flattening out in the low-temperature region. This portion appears only after rapid thermal annealing (RTA). In principle, its appearance may be caused by preliminary heavy doping of the near-contact region with a shallow donor impurity as well as doping in the course of contact formation owing to RTA, if the contact-forming layer involves a material atoms of which serve as shallow donors in III N compounds. The obtained Pc(T) dependences cannot be explained by the existing mechanisms of current transfer. We propose other mechanisms explaining the experimental Pc(T) curves for ohmic contacts to n - GaN and n -AlN