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Your search keyword '"Gevorgyan, S. G."' showing total 20 results
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20 results on '"Gevorgyan, S. G."'

3. A New Type 'Magnetic-field' Probe of High Spatial-resolution Based on a Single-layer Flat-coil Method

Author

Gevorgyan, S. G. and Azaryan, M. G.

Subjects
Condensed Matter - Other Condensed Matter
Abstract

A radically new approach to surface probing based on a replacement of the solid-state near-field probes by the 'long-field' ones is presented and discussed. Such probes may enable to create a radically new generation microscopes with non-perturbing long-range action probe based on a highly sensitive RF test method with a single-layer flat coil. This may give a start for creation of a new direction in microscopy., Comment: 4 pages, 2 figures. Journal of Contemporary Physics (Armenian Academy of Sciences), 2005, submitted [to be published by Allerton Press, Inc.]

Published
2005

4. The possibility of separation of the ideal conductive and superconductive (Meissner state) phase transitions. 2. Physical consequences following from the paramagnetic effect

Author

Gevorgyan, S. G.

Subjects
Condensed Matter - Superconductivity
Abstract

In the first part of this work an overview of the available data on the paramagnetic effect recently discovered in superconductors was given as well as a possible explanation of the effect. Here the consequences caused by this weakly expressed phenomenon and following from the analysis of the shape of the transition curve are discussed, as well as conclusions based on the test data and, important for true understanding of the nature of superconductivity., Comment: 6 pages, 2 figures

Published
2005

12. Imaging of the Local Dissipation in YBCO Coated Tapes.

Author

Kiss, T., Inoue, M., Egashira, S., Yasunaga, M., Tokutomi, H., Takeo, M., Shirinyan, H. G., Gevorgyan, S. G., Lijima, Y., Kakimoto, K., and Saitoh, T.

Subjects
ENERGY dissipation, LOW temperature engineering, MICROSCOPY, PERCOLATION theory, STATISTICAL physics, FORCE & energy
Abstract

Current transport properties in YBCO coated tapes have been studied by the low temperature scanning laser microscopy (LTSLM) as well as the four-probe method. The LTSLM measurement allows us to visualize the local resistive transition with a spatial resolution of a few μm. It has been shown that the localized resistive region percolates into the sample as the bias current density is increased. From the LTSLM measurements, we can estimate the spatial distribution of the inhomogeneous Jc. Relationship between the local Jc distribution and the global E-J characteristics has also been investigated. The percolation probability obtained based on the LTSLM measurement agreed quantitatively with that of the four-probe measurement. Namely, those two measurements support the percolation model. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2004
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18. FLAT COIL -BASED TUNNEL DIODE OSCILLATOR CAPABLE OF IMAGING THE PROPERTIES OF HTSC FILMS WITH ABOUT 3 MICROMETER SPATIAL RESOLUTION.

Author

Gevorgyan, S. G., Shirinyan, H. G., Manukyan, A. M., Sarkisyan, A. G., and Polyanskii, A.

Subjects
*IMAGING systems, *LASER beams, *ELECTRIC inductance, *ELECTRIC oscillators, *DIODES, *AMPLITUDE modulation
Abstract

A new imaging method has been developed and tested (using a focused He-Ne laser beam as a probing signal), capable of imaging the properties of HTSC films with ∼3 μm spatial resolution. The method is based on detection of the inductance and Q-factor value changes of a single-layer flat coil, placed at the face of the sample. This leads to frequency and/or amplitude changes of the stable tunnel diode oscillator. The test device enabled 2D-mapping of the grain structure of a bridge-shaped YBaCuO film. Basically, the method is capable of imaging 2D-current distribution and identifies localized defects in thin HTSC materials with sub-μm spatial-resolution, using non-bolometric response. However, the achieved resolution ∼3 μm of a bolometric nature (in a given device with 3.5 mm-size coil) by no means is limited by the abilities of the method, but mainly, it depends on how narrowly it is possible to focus the probing beam, while the own resolution of the present flat coil-based technique is better than 0.1 μm, and can be improved essentially by reducing the coil size. [ABSTRACT FROM AUTHOR]

Published
2004

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