The preparation and electrical properties of Bi₂Sr₂CaCu₂O_ythick films with high T_con (100) MgO substrate

Abstract

Thick c-oriented films of single-phase Bi2SrzCaCu20, were prepared on (100) MgO substrates by employing a partial melting method. The effect of quenching on T,, was studied. The highest T,o obtained by resistance measurement was 92 K, whereas 93.2 K was achieved by AC susceptibility measurements. The best results for the critical current density Jc, measured in zero magnetic field, were 1.3 x lo3 A Near Tc the temperature dependence of Jc can be described by Jc -(1 -TITo)'.At temperatures T << To the dependence of Jc on temperature can be described by a homogeneous superconductor flux creep model. at 77 K and 7 x lo3 A c m 2 at 53 K.

Growth and characterization of Bi2Sr2CaCu2Oythick films on bare polycrystalline Y-stabilized ZrO2substrates

“…The powders of Bi 2 O 3 , SrCO 3 , CaCO 3 and CuO were ground in an agate mortar, pressed and sintered three times in an Ar atmosphere for 6 h at 760, 765 and 820 • C successively. The final sintering steps were performed in an O 2 atmosphere at 850 • C for 6 h and 860, 866 and 870 • C for 2 h. For each sintering step the pellets were ground and pressed [10].…”

“…Several millilitres of acetone were added to form a suspension which was deposited on a polycrystalline YSZ substrate with a diameter of 10 mm to form a uniform film after the evaporation of the acetone. This procedure was repeated several times to control the thickness of the films [10]. The deposited powders were then put into a muffle furnace.…”

Laser zone melted Bi2Sr2CaCu2O8+ thick films on (100) MgO substrate

“…On the other hand, Zhang [12] arrived at the conclusion that well aligned Bi-2212 grains can be obtained by melt processing on MgO(100) when the film thickness is less than 25 µm. Thick c-oriented films of single-phase Bi-2212 have been grown on (100) MgO substrates by employing a partial melting method [17]. The best J c values obtained were 1300 A cm −2 at 77 K in the case of films with a thickness of 30 µm.…”

HREM of High‐T c Bi‐2212 Superconducting Films on Vicinal Substrates

“…The experimental set-up is described in [3,4]. For deposition, stoichiometric Bi-2212 targets [5] and a UV KrF-eximer laser (λ = 248 nm, Φ~3.7J/cm 2 , laser spot size on the target ~1mm 2 , target-substrate distance = 30mm, laser pulse duration and repetition rate were 25ns and 1 Hz respectively) were used. During deposition the substrate temperature was held at 800 ± 1°C, with 2.5 mbar oxygen background pressure, and the growth rate was about 0.12 nm/pulse.…”