Influence of the spark-plasma texturing conditions on the intragranular features of Bi-2223 ceramic samples
Abstract
The influence of the spark-plasma texturing (SPT) conditions on the intragranular superconducting properties of Bi 1.65 Pb 0.35 Sr 2 Ca 2 Cu 3 O 10 + δ (Bi-2223) samples has been investigated. Also, the SPT samples were subjected to a post-annealing heat treatments (PAHT) in different times. Intragranular superconducting features, extracted from magnetoresistance measurements, ρ(T, H) , in applied magnetic fields up to 9 T, were studied by analyzing the temperature dependence of the in-plane upper critical field, Hc2ab(T), and the magnetic field dependence of the pinning energy at zero temperature, U(0, H). The results indicated that, before and after the PAHT, values of the Hc2ab(0), obtained by using the Werthamer–Helfand–Hohenberg formula, increased ∼ 21 % , i.e., from 115.8 to 140.2 T. We have also found that the effective intragranular pinning energy at zero applied magnetic field, U= U(0 , 0) , also increased over approximately three times, from 0.28 to 0.98 eV. These results strong strongly indicate that the SPT process is responsible for inducing deoxygenation at the intragranular level of ceramic samples, a feature presumably occurring near of the end of planar defects. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
Keywords
Annealing
Calcium compounds
Ceramic materials
Copper compounds
Lead compounds
Magnetic fields
Strontium compounds
Temperature distribution
Applied magnetic fields
Magnetic field dependences
Magnetoresistance measurements
Post annealing heat treatments
Spark plasma texturing (SPT)
Superconducting properties
Temperature dependence
Upper critical fields
Bismuth compounds