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1

Conductivity and Superconductivity of (Bi,Pb)_4Sr_3Ca_3Cu_4O_x Glass-Ceramics

100%

Gazda M., Kusz B., Stizza S., Chudinov S., Natali R., Piętosa J., Bienias A.

Acta Physica Polonica A

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2004

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vol. 106

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issue 5

617-625

EN

In the (Bi,Pb)-Sr-Ca-Cu-O system, materials of various electrical and superconducting properties may be produced by a glass-ceramic method. Phase composition, structure, microstructure and also electrical properties of the material change as a result of heat treatment. Depending on the heat treatment conditions, either a superconductor with the critical temperature between 8 and 105 K or material without a superconducting transition may be obtained. The properties of the material change so much because during annealing three oxide superconductors belonging to the bismuth family are formed. (Bi_{0.8}Pb_{0.2})_4Sr_3Ca_3Cu_4O_x glass was prepared by a standard technique of quenching homogenized and melted substrates. The glass-ceramic samples were obtained by annealing of the glass beneath melting temperature. Structure and microstructure of glass-ceramic samples were studied with scanning electron microscopy and X-ray diffraction method. Superconducting properties were studied by means of electrical conductivity and magnetization measurements. In this paper we present the influence of the phase composition, structure and microstructure on the electrical conductivity in the normal state and the superconducting properties of (Bi,Pb)_4Sr_3Ca_3Cu_4O_x glass-ceramics.

2

Conductivity and Superconductivity of (Bi,Pb)_4Sr_3Ca_3Cu_4O_x Glass-Ceramics

100%

Gazda M., Kusz B., Sobiechowska E.

Acta Physica Polonica A

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2007

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vol. 111

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issue 5

713-719

EN

(Bi,Pb)-Sr-Ca-Cu-O glasses, annealed in proper conditions, transform into a granular metal and superconductor. As a result of annealing oxide superconductors belonging to the bismuth family (Bi,Pb)_2Sr_2CuO_x, (Bi,Pb)_2Sr_2 CaCu_2O_x, and (Bi,Pb)_2Sr_2Ca_2Cu_3O_x crystallize. (Bi,Pb)-Sr-Ca-Cu-O glass-ceramic samples were obtained by annealing the amorphous solid at temperatures between 500°C and 870°C. Their microstructure was studied with scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The temperature dependence of resistivity in annealed samples was studied in a temperature range from 3 K to 300 K. In this work we present the influence of the microstructure on the electrical properties of the granular and disordered material composed of the 2201 and 2212 grains embedded in the nonmetallic matrix.

3

Study of Composites Consisting of High-T_{c} Superconductor and Fine Magnetic Particles

100%

Timko M., Kopčanský P., Kováč J., Koneracká M., Plecháček V.

Acta Physica Polonica A

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2000

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vol. 97

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issue 3

389-392

EN

The composite systems as a mixture of fine magnetic particles of Fe_{3}O_{4} and superconducting powder such as Bi_{1.8}Pb_{0.2}Sr_{2}Ca_{2}Cu_{3}O_{10+x} were prepared. The influence of internal magnetic field (generated by magnetic particles) on the superconducting properties of prepared composites were studied as a function of concentration of magnetic particles and their magnetic state. The observed data both of the shielding and the Meissner effect were compared with corresponding linear combination of pure signals of magnetite and superconductor, respectively. The large differences were observed for demagnetized samples. It means that result must be discussed in the frame of the distribution of internal magnetic field created by the magnetic particles.

4

Epitaxial Intergrowth of Isostructural Phases in Bi-2212 Single Crystals

100%

Babonas G.-J., Leonyuk L., Maltsev V.

Acta Physica Polonica A

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1997

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vol. 92

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issue 1

251-254

EN

The isostructural phases in Bi-2212-type HTSC were studied by structural and optical methods. The epitaxial intergrowth was shown to be a feature typical of single crystals composed of several isostructural phases. The physical properties of the multi-phase samples were interpreted on the basis of reference mono-phase samples. A presence of the intergrowth interface was assumed to be responsible for particular features in multi-phase samples.

5

Superconducting Properties of BiPbSrCsCuO and BiSrCaCuO Glass-Ceramics

100%

Miller W., Borówko K., Gazda M., Stizza S., Natali R.

Acta Physica Polonica A

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2006

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vol. 109

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issue 4-5

627-631

EN

In this work we study the main differences between the superconducting properties of the Bi_4Sr_3Ca_3Cu_4O_x and (Bi_{0.8}Pb_{0.2})_4Sr_3Ca_3Cu_4O_x glass-ceramics. The Bi_4Sr_3Ca_3Cu_4O_x and (Bi_{0.8}Pb_{0.2})_4Sr_3Ca_3Cu_4O_x glass-ceramics prepared in the same conditions contain similar amounts of the superconducting 2212 phase, however their superconducting and normal-state electrical properties differ significantly. The main reason which makes BiSrCaCuO glass-ceramics worse superconductor than BiPbSrCaCuO is its microstructure.

6

Superconducting Transition in Granular Bi-Sr-Ca-Cu-O Superconductors

80%

Gazda M., Kusz B., Sadowski W., Stizza S., Natali R., Di Stasio V.

Acta Physica Polonica A

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2006

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vol. 109

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issue 4-5

485-491

EN

In this work we study the superconducting transition in the samples containing relatively small granules of high-T_c Bi-Sr-Ca-Cu-O superconductors. The samples were obtained by the glass-ceramic technology. Two-stage character of the superconducting transition was studied. Pairing transition temperature depends on the magnetic field. Coherence transition is very sensitive to the current flowing through the sample, magnetic field and the phase composition and microstructure of the sample. The analysis of superconducting transition by means of the logarithmic derivative of the fluctuation conductivity shows the mesoscopic granularity of the samples.

7

Scanning Tunneling Spectroscopy Sensitive to Layer Structure of BSCCO

80%

Aleszkiewicz M., Aleszkiewicz P., Raułuszkiewicz J.

Acta Physica Polonica A

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1997

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vol. 91

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issue 3

597-604

EN

Scanning tunneling microscopy images and scanning tunneling spectroscopy characteristics were measured at 4.2 K in liquid helium bath on the cleaved in air a-b surface of Bi_{2}Sr_{2}CaCu_{2}O_{8} (BSCCO-2212). Electronic densities of states and superconductivity parameters Δ and Γ evaluated from dI/dV characteristics depend on tip-sample distance s: with shortening of the distance s superconducting gap structure becomes more distinct, i.e. Δ increases and Γ decreases. We explain this phenomenon as a non-vacuum tunneling, where for longer s tunneling electrons reach only the surface contamination layer on non-metallic BiO top-surface layer, whereas for shorter s tunneling electrons penetrate also deeper lying CuO layers reflecting their superconducting properties. The dependence of Δ on s is evaluated. This result allows to understand better the non-vacuum scanning tunneling microscopy imaging: by adjusting properly the tip-sample distance one can select suitable local density of states contributing dominantly to the scanning tunneling microscopy images taken on BSCCO.

8

Muon Spin Rotation Studies of the Vortex Matter in the High-T_{c} Superconductor Bi_{2}Sr_{2}CaCu_{2}O_{8+δ}

80%

Blasius T., Niedermayer C., Tallon J., Pooke D., Golnik A., Noakes D., Stronach C., Ansaldo E., Henn R., Lin C., Bernhard C.

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vol. 96

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issue 2

245-258

EN

We report muon spin rotation studies of the magnetic field distribution n(B) in the vortex state of the high-temperature superconductor Bi_{2}Sr_{2}CaCu_{2}O_{8+δ}. From our data on three sets of overdoped, nearly optimized and underdoped single crystals we obtain evidence for a two-stage melting process of the vortex matter under equilibrium conditions. In the irreversible regime well below the irreversibility line we observe a transition in the vortex state which we associate with an intra-planar melting transition. The resulting flux-line liquid phase persists over a sizeable temperature interval before the inter-planar decoupling of the individual vortex lines takes place in a second step at the irreversibility line, resulting in a pancake liquid phase.

9

Specific Heat and Magnetoresistance of Y-, Tl- and Bi-Type High-Temperature Superconductors

70%

Zalecki R., Kozłowski A., Kołodziejczyk A., Gritzner G., Mair M.

Acta Physica Polonica A

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1997

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vol. 91

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issue 2

431-434

EN

Specific heat of polycrystalline DyBa_{2}Cu_{3}O_{7} and Tl_{0.58}Pb _{0.42}Sr_{1.6}Ba_{0.4}Ca_{2}Cu_{3}O_{9} samples, as well as the single crystal of Bi_{2}Sr_{2}CaCu_{2}O_{8} have been measured within the temperature interval from 50 to 250 K. For Dy- and Tl-specimens the pronounced jump in specific heat and apparent contribution from Gaussian fluctuations of superconducting order parameter close to T_{c} have been observed. In contrary, for Bi-specimen only a rounded maximum within a broad interval around T_{c} has been detected. Magnetoresistance measurements as a function of temperature just below T_{c} have been carried out for Dy- and Tl-samples and the slopes of upper critical fields have been determined. The data have been analysed within a frame of Ginzburg-Landau-Abrikosov- Gorkov theory with additional Gaussian-like fluctuation term. The electronic specific heat coefficients γ, and the coherence length χ have been obtained.

10

Scanning Probe Microscopy and Spectroscopy of High Temperature Superconductors

61%

de Lozanne A., Edwards H., Yuan C., Markert J.

Acta Physica Polonica A

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1998

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vol. 93

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issue 2

333-342

EN

The authors review recent studies of high temperature superconductors conducted with scanning tunneling and magnetic force microscopes. Emphasis is placed on the importance of surface and probe characterization, both of which are likely to affect the detailed nature of the observations.

Refine search results

Conductivity and Superconductivity of (Bi,Pb)_4Sr_3Ca_3Cu_4O_x Glass-Ceramics

Conductivity and Superconductivity of (Bi,Pb)_4Sr_3Ca_3Cu_4O_x Glass-Ceramics

Study of Composites Consisting of High-T_{c} Superconductor and Fine Magnetic Particles

Epitaxial Intergrowth of Isostructural Phases in Bi-2212 Single Crystals

Superconducting Properties of BiPbSrCsCuO and BiSrCaCuO Glass-Ceramics

Superconducting Transition in Granular Bi-Sr-Ca-Cu-O Superconductors

Scanning Tunneling Spectroscopy Sensitive to Layer Structure of BSCCO

Muon Spin Rotation Studies of the Vortex Matter in the High-T_{c} Superconductor Bi_{2}Sr_{2}CaCu_{2}O_{8+δ}

Specific Heat and Magnetoresistance of Y-, Tl- and Bi-Type High-Temperature Superconductors

Scanning Probe Microscopy and Spectroscopy of High Temperature Superconductors