Superconducting properties of an Ag-CLAD (BiPb)_2Sr_2Ca_2Cu_3O_10+y tape

AC susceptibility and V-I characteristics of a well characterised Ag-clad Bi-Pb-Sr-Ca-Cu-O tape have been studied in the temperature (T) range 77-106 K and magnetic fields (B) up to 0.06 T. The intrinsic critical current density J_s (from ac susceptibility) is 30000 A/cm2 at 77 K whereas the transport critical current density Jc (from V-I curves) is 10100 A/cm2 at the same temperature. Both Js and Jc showed power law variations with T and B, respectively, characteristic for intragranular flux creep. From the dissipation within the core the differential resistance Rf (associated with the flux flow) has been deduced. The magnitude and the variations of Rf with T and B are consistent with those due to flux flow in type II superconductors in low field. From d^2 V/d I^2 vs I curves very broad critical current distribution CCD has been deduced

Sintesis Komposit Superkonduktor Bpscco/Ag Menggunakan Metode Padatan

Penelitian ini bertujuan untuk membuat komposit superkondutor Bi1,6Pb0,4Sr2Ca2Cu3AgxO10+ dengan nilai x = 0,5 dan x = 1,0. metode yang digunakan dalam sintesis superkonduktor adalah metode padatan, dimana semua bahan digerus sampai benar-benar halus dan homogen, dikalsinasi, digerus ulang, dicetak berbentuk silinder panjang dan disintering. Waktu dan suhu sintering untuk sampel 1 dan sampel 2 sama yaitu 96 jam pada suhu konstan 840oC. Karakterisasi yang dilakukan yaitu uji Meissner dan uji Tc. Dari hasil uji Meissner tidak menunjukkan adanya efek Meissner yang kuat yaitu sampel 1 tidak mengalami pergeseran sama sekali sedangkan sampel 2 mengalami pergeseran saja ketika supermagnet diletakkan di atas sampel yang direndam dalam nitrogen cair. Dari hasil uji Tc, belum menunjukkan suhu kritis superkonduktor fasa 2223 (110K) yaitu untuk sampel 1 suhu kritisnya 83 K sedangkan sampel 2 suhu kritisnya 108 K. Komposit superkondutor Bi1,6Pb0,4Sr2Ca2Cu3AgxO10+ dengan nilai x = 0,5 dan x = 1,0. belum mampu menunjukkan sifat superkonduktivitas yang lebih bai

Xrd Analysis of Bi-2212 Superconductors: Prepared by the Self-flux Method

An experiment had been carried out on formation of Bi-2212 crystals with the self-flux method. Flux was used and derived from CuO and CaCO3. The process of synthesis was equipped with the melting process at temperature 890 °C with time variation of melting 35 minutes and 40 minutes, followed by slow cooling at a rate of 1°C/hour for 70 hours. The results were obtained and characterized by XRD test. This research aimed to produce superconducting materials with self-flux method, calculate the percentage of the value of the volume fraction, the percentage of oriented phase and impurities. Samples generated from XRD measurements were made to match with the XRD Strobell's pattern of the superconducting Bi-2212 standards. The results showed that the value of the volume fraction of 2212 phase and the phase of the highest oriented melting at 40 minutes were equal to 67.68% and 38.89%, while the smallest impurity phase of 32.32% were obtained at the same time melting

Doping Dependence Of Magnetic Susceptibility And Electrical Properties Of High Temperature Superconducting Ceramics

It has been well known that Bi-Sr-Ca-Cu-O system has three superconducting phases represented by general formula, Bi2Sr2Can-1CUnOy , referred to as 2201(n= 1,Tc~ 10K), 2212 (n=2, Tc~ 80K), and 2223 (n = 3, Tc~ 11 OK) The role of calcium and copper seem to influence the formation of those phases This research work was focussed at the role played by calcium in the formation of 2223 phase by doping this site with different elements having different valences and ionic radius Sample of Bi2-xbpxSr2Ca2Cu3O3(x=01 to 06)and Bi2Pb06Sr2Ca2-"MxCu3Oy (M = Ba, Y, V, Zn, Sn with x =0 02 to 0 10) were prepared using the conventional solid state reaction technique The samples were sintered at 855°C for 150 hours and annealed at 830°C for 30 hours The transport properties of the samples were measured using four-point probe resistance measurement, magnetic properties by using ac susceptibility, microstructure by scanning electro

Addition of Co3O4 to introduce pinning centre in Bi-Sr-Ca-Cu-O/Ag tapes

This study investigated the flux pinning capability of Co3O4 in Bi-Sr-Ca-Cu-O superconductor tapes. The Bi-Sr-Ca-Cu-O powders were prepared by using the co-precipitation technique with the addition of Co3O4 as pinning centre to enhance the transport critical current density (Jc) of the system. The Ag sheathed (Bi,Pb) 2Sr2Ca2Cu3O10 (2223) and (Bi,Pb) 2Sr2Ca2Cu3O10- ( Co3O4)0.01 high temperature superconductor tapes were fabricated using the powder in tube method. The effects of Co3O4 addition on the microstructure, critical temperature and critical current density were studied. The Jc value of the Co3O4 added tapes increased to ~4500 A/cm2. This tape showed the highest Jc and Tc when heated at 845°C for 50 hours. XRD diffraction pattern showed that the addition of Co3O4 inhibits the 2223 phase formation. This study shows that magnetic particles can act as effective pinning centres leading to the enhancement of Jc in the system

Giant dispersion of critical currents in superconductor with fractal clusters of a normal phase

The influence of fractal clusters of a normal phase on the dynamics of a magnetic flux trapped in a percolative superconductor is considered. The critical current distribution and the current-voltage characteristics of fractal superconducting structures in the resistive state are obtained for an arbitrary fractal dimension of the cluster boundaries. The range of fractal dimensions, where the dispersion of critical currents becomes infinite, is found. It is revealed that the fractality of clusters depresses of the electric field caused by the magnetic flux motion thus increasing the critical current value. It is expected that the maximum current-carrying capability of a superconductor can be achieved in the region of giant dispersion of critical currents.Comment: 7 pages with 3 figure