IMAGING OF THE GRAIN STRUCTURE OF THIN HTS FILM BY A SINGLE-LAYER FLAT-COIL-OSCILLATOR TEST-METHOD (SFCO-TECHNIQUE)

S. G. Gevorgyan; H. G. Sharinyan; G. H. Karapetyan; G. S. Gevorgyan; A. A. Polyanskii

doi:10.46991/PYSU:A/2009.43.2.050

Authors

S. G. Gevorgyan Chair of Solid State Physics, YSU, Institute Physical Researches, National Academy of Sciences, Armenia
H. G. Sharinyan Institute Physical Researches, National Academy of Sciences, Armenia
G. H. Karapetyan Chair of Solid State Physics, YSU, Institute Physical Researches, National Academy of Sciences, Armenia
G. S. Gevorgyan Chair of Solid State Physics, YSU, Armenia
A. A. Polyanskii National High Magnetic Field Laboratory, Florida State University, USA

DOI:

https://doi.org/10.46991/PYSU:A/2009.43.2.050

Keywords:

single-layer flat-coil-oscillator, SFCO, low temperature, laser scanning microscope, LTS, HTS, imaging

Abstract

An imaging technique has been created (using a focused He-Ne laser beam as a probing signal) capable of imaging the grain structure of HTS thin films with 2–3 μ spatial resolution. It is based on detection of an inductance change of a single-layer flat pick-up coil, placed at the face of the specimen. This leads to frequency changes of a stable tunnel diode oscillator. Test device enabled 2D-mapping of the grain structure of the bridge-shaped YBaCuO film. Basically, the method is capable of imaging fine peculiarities of normal-metallic to superconductive phase transition and 2D-current distribution, as well as may identify localized defects in thin HTS-materials with sub-μ spatial resolution, using non-bolometric response. However, the achieved 2–3 μ resolution of a bolometric nature (in a given device with ∼3 mm-size coil) is limited and depends on how narrow is possible to focus the probing beam, while the own spatial resolution of the tested flat-coil technique is better than 0.1 μ, and can be improved by 1–2 orders of the value by reducing pick-up coil size.