RESEARCH SCOPE

Application of macroscopic quantum effects, especially macroscopic quantum interference in superconductors with low and high values of Tc, in the field of measurement of extremely weak magnetic fields or physical quantities whose changes can be transformed to changes of magnetic flux. The research is concentrated on Josephson junctions, RF and DC SQUIDs, superconducting quantum magnetometers (SQM), gradiometric antenna systems and their applications in systems for measurement of beams intensity in accelerators, biomagnetic and geomagnetic fields.

SCIENTIFIC RESULTS :

• Contribution to theoretical clarification of the interactions in HTc superconductors based on proposed models for 2D structures and weak links in granular superconductors [7], [8], [9], [13]
• Design and verification of the measuring system SQM/MHY-1 of original conception for measurement and analysis of magnetic characteristics of the HTSC using superconducting quantum magnetometer with the SQUID sensor and superconducting gradiometric antenna of the 2nd order [10], [25]
• Investigation of magnetic properties of high-Tc superconductors ([17], [20] , YBCO hysteretic curves)
• Developed technology of preparation of the RF SQUIDs, combined methods of compensation of the disturbing signals in measurement of extremely weak magnetic fields in a magnetically unshielded environment [4], [5], [6], methods of determination of low concentrations of the ferro(ferri-) magnetic substances in the biological objects in a noninvasive way ([14], Lung Dust Loads Measurement), biomonitoring of the environment based on magnetometry
• Design of the system for measuring of intensity and radial position of a beam of electrically charged particles in the superconductive accelerator ([18], [19], [21], [22], simplified scheme)

SPECIAL EQUIPMENT :

• 5-channel low-Tc DC SQUID system with equivalent sensitivity ~20x10^-15 T Hz^-1/2 in the white noise range (gradiometers' diameter: 14mm, SQUIDs from FSU Jena - Germany)
• One-channel low-Tc RF SQUID system with equivalent sensitivity ~20x10^-15 T Hz^-1/2 in the white noise range (gradiometer's diameter: 40mm, SQUID of own production)

SELECTION OF PUBLICATIONS

1. ZRUBEC, V. - VRABCEK, P. - TEKEL, P.: Optimalization of the second order gradiometer baselength that has been designed for the measurement of weak inhomogeneous magnetic fields. Il Nuovo Cimento 2D, 1983, 2, pp.175-183.
2. VOLCKO, D.: Possible explanation of the anomalous ratio 2D_ab / k_B T_c in the range of the BCS formalism. Physica Status Solidi (b), 164, 1991, K41-K43.
3. VOLCKO, D.: Single-Particle States in a superconducting system. Physica Status Solidi (b), 167, 1991, K25.
4. SKAKALA, M. - ZRUBEC, V. - MANKA, J.: Active compensation for ambient magnetic noise in the unshielded environment. Measurement Science and Technology, 1993, 4, pp.468-472.
5. ZRUBEC, V. - MANKA, J. - SKAKALA, M.: Superconducting pick-up antenna with limited frequency bandwith. Cryogenics, 1993, 33, 10, pp.999-1004.
6. SIMACEK, I. - ZRUBEC, V. - SKAKALA, M.: RF SQUID magnetometer with simplified circuitry. Review of Scientific Instruments, 1993, 64, 8, pp.2401-2402.
7. VOLCKO, D.: A possible behaviour of weak links in granular superconductors. Physica Status Solidi (b), 178, 1993, K31-K33.
8. VOLCKO, D.: A model for deformations of two-dimensional structures. Physica Status Solidi (b), 179, 1993, K27-K29.
9. VOLCKO, D.: A possible pairing mechanism in quasi-two-dimensional structures. Physica Status Solidi (b), 175, 1993, K13-K15.
10. ZRUBEC, V. - CIGAN, A. - MANKA, J.: Simplified fast method for magnetic characteristics measurement of the HTc superconducting materials. Physica C, 223, 1994, No. 1-2, pp.90-94.
11. SIMACEK, I.- ZRUBEC, V.- MANKA, J. - URBAN, A.: Three channel magnetometer for measurement of weak magnetic fields. Elektrotechnicky casopis - Journal of Electrical Engineering 45, 1994, pp.88-90.
12. ZRUBEC, V.: Bioelectric signals in neuron structures and the Josephson effect. Medical Hypotheses, 43, 1994, pp.273-284.
13. VOLCKO, D.: Relevance of the m(T) dependence for 2D superconductivity. Physica Status Solidi (b), 181, 1994, K21-K23.
14. KRUTY, F. - SIMACEK, I. - MANKA, J. - VRABCEK, P.: Lung dust loads monitored by noninvasive magnetometric method. Central European Journal of Occupational and Environmental Medicine, 1, 1995, 1, pp.5-12.
15. VOLCKO, D.: Energy of a Josephson Junction. Physica Status Solidi (b), 188, 1995, K13.
16. ZRUBEC, V. - MANKA, J.: Optimization of noise parameters of SQUID magnetometers with external negative feedback. Cryogenics, 35, 1995, pp.451-454.
17. DANIELIK, L. - HANIC, F. - CIGAN, A. - ZRUBEC, V.- MANKA, J.: Preparation, characterization and magnetic behaviour of Pb doped superconductors. Molecular Physics Reports, 9, 1995, pp.7-13.
18. ZRUBEC, V.: Theoretical sensitivity limits of the SQUID system for measuring beam intensities of electrically charged particles in superconductive accelerators. Cryogenics, 36, 1996, pp.427-434.
19. ZRUBEC, V.: Theoretical sensitivity limits of the SQUID system for measuring the radial position of a beam of electrically charged particles in superconductive accelerators. Cryogenics, 37, 1997, pp.97-104.
20. CIGAN, A. - MANKA, J. - BUCHTA, S.: Experimental Study of the Intergranular Weak Link Structures YBa₂Cu₃O_7-x with the Help of Magnetization Measurements. Journal of Low Temp.Phys., 106, 1997, pp.447-452.
21. ZRUBEC, V. - MANKA, J.: Measurement of Beam Intensity of Electrically Charged Particles in Superconductive Accelerators using SQM. Journal of Low Temp.Phys., 106, 1997, pp.539-544.
22. MANKA, J. - ZRUBEC, V. - CIGAN, A.: Measurement of Beam Position of Electrically Charged Particles in Superconductive Accelerators using SQM. Proc. of MEASUREMENT'97 - Int. Conf. on Measurement, Smolenice, May 29-31, Eds.: I.Frollo and A.Plackova, Polygraphy of SAS Bratislava, pp.55-58.
23. SIMACEK, I. - MANKA, J. - KRUTY, F.: Sensitivity Limits of the Magnetometric Method for Measuring the Concentration of Powdered Materials. Proc. of MEASUREMENT'97 - Int. Conf. on Measurement, Smolenice, May 29-31, Eds.: I.Frollo and A.Plackova, Polygraphy of SAS Bratislava, pp.59-62.
24. ZRUBEC, V. - URBAN, A.: Superconductive quantum fluxmeter - superconductive quantum magnetometer with external feedback. Cryogenics, 37, 1997, pp.511-516.
25. ZRUBEC, V.: Theoretical sensitivity limits of the compensation method for magnetization characteristics measurement of HTc superconducting materials using LTc SQUID 2nd order gradiometer. Cryogenics, 39, 1999, pp.241-251.
26. CIGAN, A. - MANKA, J. - MAIR, M. - GRITZNER, G. - PLESCH, G. - ZRUBEC, V.: Influence of the Tl- and Hg-content on magnetic and transport properties of the Pb, Sr-doped Tl-1223 and Hg-1223 superconductors. Physica C, 320, 1999, pp.267-276.
27. PLESCH, G. - CIGAN, A. - MANKA, J. - BUCKULIAKOVA, A. - HANIC, F. - BUCHTA, S. - ANDRZEJEWSKI, B. - STANKOWSKI, J.: Magnetic properties of YBa₂Cu₃O_7-d melt textured samples prepared by powder melting process and quench and melt growth techniques. Acta Physica Polonica A, 98, 2000, pp.327-334.
28. CAMBEL, V. - KARAPETROV, G. - ELIAS, P. - HASENÖHRL, S. - KWOK, Wai-Kwong - KRAUSE, J. - MANKA, J.: Approaching the pT range with a 2DEG InGaAs/InP Hall sensor at 77 K. Microelectronic Engineering, 51-52, 2000, pp.333-342.
29. CHROMIK, S. - JERGEL, M. - HANIC, F. - JIMENEZ, S. - JERGEL, M. - STRBIK, V. - FALCONY, C. - BENACKA, S. - CHEANG-WONG, J.C. - ANDRADE, E.: Preparation and properties of precursors BA-Ca-Cu-(O,F) thin films deposited from fluorides for superconducting Tl- and Hg-based films. Thin Solid Films, 375, 2000, pp.129-133.
30. HANIC, F. - CIGAN, A. - BUCHTA, S. - MANKA, J. - VOLCKO, D. - ZRUBEC, V.: Single Domain Textured (YBa₂Cu₃O_7-d)_1-x(Ag₂O)_x Samples. Physica C, 341-348, 2000, pp.575-576.
31. BANACKY, P. - PELIKAN, P. - VALKO, M. - BUCHTA, S. - HANIC, F. - CIGAN, A.: Electron Paramagnetic Resonance of High-Tc Superconducting Composites YBa₂Cu_3-xSc_xO_6±d. J.Phys.Chem. B, 105, 2001, pp.1943-1946.
32. ZRUBEC, V.: Improved system for measurement of the magnetization characteristics of high-temperature superconductors by the compensation method in weak magnetic fields. Rev.Sci.Instrum. 72, 2001, pp.2653-2660.
33. HOSTE, S. - VAN DRIESSCHE, I. - BRUNEEL, E. - PLESCH, G. - CIGAN, A. - MANKA, J.: Influence of silver doping on the microstructure and magnetic properties of YBa₂Cu₃O₇/Ag composities. Ceramics-Silikaty, 45, 2001, pp.76-80.