Temperature In Bi Research Articles

High magneto-Seebeck effect at room temperature in Bi1.8Sb0.2Te3-ySey crystal

We report thermoelectric and electrical transport properties of Bi1.8Sb0.2Te3-ySey by tuning y. In contrast to the reported p-type conductivity of the end compounds with y = 0 and 3, a dominant n-type conduction mechanism is observed for y = 1.5 from the Hall measurement. Intriguingly, the magneto-Seebeck consequence is enhanced up to ∼ 20 times for y = 1.5 compared to the end members. The reasonable value of magnetoresistance with an anisotropic character with respect to the direction of the magnetic field is observed at low temperature, which decreases with increasing temperature. The density of state at the Fermi level near room temperature correlates high Seebeck coefficient as well as magneto-Seebeck effect. High magneto-Seebeck effect at room temperature is promising for the application.

Creep of Cu-Bi Alloys with High Bi Content Near and Above Melting Temperature of Bi

Cu-Bi alloy with high Bi content can be used for thermal surge protection and energy storage. For these applications, creep at high temperatures, including temperatures above the melting temperature of Bi, Tm,Bi, becomes important. Accordingly, the creep behavior of Cu-Bi alloys, comprising 30 and 40 vol pct Bi, was studied under compression at temperatures above and below Tm,Bi. At 200 °C, which is below Tm,Bi, Cu-Bi showed a stress exponent of ~ 4 at high stresses and ~ 1 at low stresses. Finite element analysis revealed that the creep behavior of Cu-Bi at 200 °C was predominantly governed by Bi. On the other hand, at temperatures higher than Tm,Bi, Cu-Bi showed a short transient stage at high stresses, followed by sudden failure of the material. However, at low stresses, the sample first continued to expand and then started to accumulate compressive strain. A qualitative model based on interaction between liquid Bi and Cu is developed to explain the observed creep behavior at temperatures higher than Tm,Bi. The results obtained here shed light on the creep behavior of alloys with constituents having significantly different creep behavior and containing a non-reacting liquid phase.

Low superfluid density and possible multigap superconductivity in theBiS2-based layered superconductorBi4O4S3

The magnetic penetration depth $\ensuremath{\lambda}$ as a function of temperature in Bi${}_{4}$O${}_{4}$S${}_{3}$ was studied by muon-spin-spectroscopy measurements. The superfluid density of Bi${}_{4}$O${}_{4}$S${}_{3}$ is found to be very low. The dependence of ${\ensuremath{\lambda}}^{\ensuremath{-}2}$ on temperature possibly suggests the existence of two $s$-wave-type energy gaps with the zero-temperature values of 0.93 (3) and 0.09 (4) meV. The upturn in the temperature dependence of the upper critical field close to ${T}_{\mathrm{c}}$ further supports multigap superconductivity in Bi${}_{4}$O${}_{4}$S${}_{3}$. The presence of two superconducting energy gaps is consistent with theoretical and other experimental studies. However, a single-gap $s$-wave model fit with a gap of 0.88 (2) meV cannot be ruled out completely. The value of $\ensuremath{\lambda}(T)$ at $T=0$ K is estimated to be $\ensuremath{\lambda}(0)=861\phantom{\rule{0.16em}{0ex}}(17)$ nm, one of the largest of all known layered superconductors, reflecting a very low superfluid density.

Substrate dependent structural and electrical properties of Bi2Cu0.1V0.9O5.35 solid electrolyte thin films

Abstract High ion conducting room temperature stabilized γ-Bi 2 Cu 0.1 V 0.9 O 5.35 has been successfully synthesized in thin film form on glass and alumina substrates. The films were characterized for their structural properties like XRD, SEM, EDAX and AFM. Bi 2 Cu 0.1 V 0.9 O 5.35 films deposited on alumina substrate showed single-phase nature with tetragonal crystal structure. The AFM study reveals the considerable change in growth morphology on alumina substrate. The temperature dependent ionic conductivity of Bi 2 Cu 0.1 V 0.9 O 5.35 films synthesized on glass and alumina substrates were studied using impedance spectroscopy. The high ionic conductivity has been observed at lower temperature for Bi 2 Cu 0.1 V 0.9 O 5.35 thin films synthesized on alumina substrates. With these comparisons, alumina substrate proves its candidature for deposition of Bi 2 Cu 0.1 V 0.9 O 5.35 films for solid oxide fuel cell applications.

Analysis of a Joint Method Between Superconducting YBCO Coated Conductors

This paper deals with an analysis on the optimum lap joint method of the YBCO coated conductor (CC) wire. Effective low resistance joint is important for the development of persistent current mode system using the second generation high temperature superconducting (2G HTS) wire, YBCO CC. CC tape is stacked with copper or stainless steel stabilizer, silver layer, YBCO layer, buffer and substrate. The joint between CCs was performed with low temperature InBi solder. YBCO samples with various contact conditions were fabricated and tested. Characteristics of jointed CC tape were evaluated from the V-I curve and contact resistance was derived from experimental results. Characteristics of jointed CC were investigated by electrical analysis and optical micrograph. The BSCCO wires were jointed at different conditions, and the results were compared with the joint between the YBCO CCs.

Anomalously high charge/orbital ordering temperature in Bi 0.5 Sr 0.5 MnO 3

Neutron/synchrotron diffraction data and magnetic measurements provide direct evidence of charge/orbital ordering at anomalously high temperatures in Bi0.5Sr0.5MnO3, as well as in other (Bi,Sr)MnO3 manganites. We report on the electronic and magnetic transitions of these oxides. The origin of the high value of the charge/orbital ordering temperature is discussed.

Reversible melting and equilibrium phase formation of (Bi, Pb)2Sr2Ca2Cu3O10+δ

The decomposition and the re-formation of the (Bi, Pb)2Sr2Ca2Cu3O10+δ (Bi, Pb(2223)) phase have been investigated in situ by means of high-temperature neutron diffraction, both in sintered bulk samples and in Ag-sheathed monofilamentary tapes. Several decomposition experiments were performed at various temperatures and under various annealing atmospheres, under flowing gas as well as in sealed tubes, in order to study the appropriate conditions for Bi,Pb(2223) formation from the melt. The Bi,Pb(2223) phase was found to melt incongruently into (Ca, Sr)2CuO3, (Sr, Ca)14Cu24O41 and a Pb,Bi-rich liquid phase. Phase re-formation after melting was successfully obtained both in bulk samples and in Ag-sheathed tapes. The possibility of crystallizing the Bi,Pb(2223) phase from the melt was found to be extremely sensitive to the temperature and strongly dependent on the Pb losses. The study of the mass losses due to Pb evaporation was complemented by thermogravimetric analysis which proved that Pb losses are responsible for moving away from equilibrium and therefore hinder the re-formation of the Bi,Pb(2223) phase from the melt. Thanks to the full pattern profile refinement, a quantitative phase analysis was carried out as a function of time and temperature and the role of the secondary phases was investigated. Lattice distortions and/or transitions were found to occur at high temperature in Bi,Pb(2223), Bi,Pb(2212), (Ca, Sr)2CuO3 and (Sr, Ca)14Cu24O41, due to cation diffusion and stoichiometry changes. The results indicate that it is possible to form the Bi,Pb(2223) phase from a liquid close to equilibrium conditions, such as Bi(2212) and Bi(2201), and open new unexplored perspectives for high-quality Ag-sheathed Bi,Pb(2223) tape processing.

C-axis resistance peak above the critical temperature in layered superconductors.

The possibility of fully describing the behavior of transverse resistivity {rho}{sub {ital c}} in cuprate superconductors exclusively in terms of some recently proposed normal-state models is discussed. It is shown that these models do not give a completely satisfactory description of the apparent singularity in {rho}{sub {ital c}} at the critical temperature in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{ital x}}, and that they fail to describe data concerning a lower-{ital T}{sub {ital c}} cuprate superconductor as Bi{sub 2}Sr{sub 2}CuO{sub 6+{ital x}} ({ital T}{sub {ital c}}{approx_equal}15 K). It is argued that these difficulties cannot be overcome considering the normal-state contribution to {rho}{sub {ital c}} only. The role of the density of states fluctuations in the behavior of {rho}{sub {ital c}} just above the transition temperature is recalled. It is shown that, taking into account this contribution, it is possible to dramatically simplify the description of the normal-state transverse resistivity. This can give important hints for the understanding of the transverse electrical transport properties of these materials. {copyright} {ital 1996 The American Physical Society.}

The elastic energy loss related to the lattice instabilities above room temperature in Bi1.7Pb0.3Sr2Ca2Cu30y

AbstractThe tensile test, the torsional pendulum test, and X‐ray analysis are used to investigate the lattice instabilities of Bi1.7Pb0.3Sr2Ca2Cu3Oy ceramics from room temperature to 250 °C. The results show that there are three energy loss peaks near 35, 95, and 155 °C, which display of strain amplitude dependence and frequency independence. In the vicinity of these peak temperatures step‐like changes of lattice parameters associated with lattice instabilities are observed.

DEGRADATION OF Bi2Sr2Ca2Cu3Oy CERAMICS

The decrease of grain superconducting transition temperature of Bi 2 Sr 2 Ca 2 Cu 3 O y ceramics on low-temperature thermocycling has been revealed and studied. Results indicate that the multi-phase samples degrade more quickly and more considerably than the single-phase samples.