Stabilization of high Tc phase in bismuth cuprate superconductor by lead doping

It has been widely ascertained that doping of lead in Bi-Sr-Ca-Cu-O systems promotes the growth of high T sub c (110 K) phase, improves critical current density, and lowers processing temperature. A systematic study was undertaken to determine optimum lead content and processing conditions to achieve these properties. A large number of samples with cationic compositions of Bi(2-x)Pb(x)Sr2Ca2Cu3 (x = 0.2 to 2.0) were prepared by conventional solid state reaction technique. Samples of all compositions were annealed together at a temperature and characterized through resistance temperature (R-T) measurements and x ray diffraction to determine the zero resistance temperature, T sub c(0) and to identify presence of phases, respectively. The annealing temperature was varied between 790 and 880 C to optimize processing parameters. Results are given. In brief, an optimum process is reported along with composition of leaded bismuth cuprate superconductor which yields nearly a high T sub c single phase with highly stable superconducting properties

Stabilization of high T(sub c) phase in bismuth cuprate superconductor by lead doping

It has widely been ascertained that doping of lead in Bi:Sr:Ca:Cu:O systems promotes the growth of high T(sub c) (110 K) phase, improves critical current density, and lowers processing temperature. A systematic investigation is undertaken to determine optimum lead content and processing conditions to achieve these. A large number of samples with cationic compositions of Bi(2-x)Pb(x)Sr2Ca2Cu3 (x = 0.2 to 2.0) were prepared by conventional solid state reaction technique. Samples of all compositions were annealed together at a temperature and characterized through resistance-temperature (R-T) measurements and x ray diffraction (XRD) to determine the zero resistance temperature, T(sub c)(0) and to identify presence of phases, respectively. The annealing temperature was varied between 790 C to optimize processing parameters. Results are given. In brief, an optimum process is reported along with composition of leaded bismuth cuprate superconductor which yields nearly a high T(sub c) single phase with highly stable superconducting properties

Electronics with superconducting devices

309-318Superconducting devices are likely to lead to the development of new and improved electronic circuits and systems. Though the operation of these devices is likely to be at liquid nitrogen temperature, they will show several improvements such as low noise, high sensitivity, less degradation due to electro-migration and other thermal effects over the ones operated at room temperature. The main driving forces for the development of superconducting electronics are: high speed, low power consumption and high sensitivity. In this paper, development of superconducting electronic components is reviewed, specially in the light of the current research on high temperature superconductors. Present status on passive and active electronic components based on low temperature superconductors is also given. Microwave applications, digital high speed devices and circuits using passive superconductive components and Jospehson junction are presented. Efforts to develop a transistor-like device are summarized. Work carried out in our laboratories is briefly reported. It is concluded that there is a great possibility of development of high temperature superconducting devices for low-noise, high-speed and low-power consuming electronic devices

Window size effect on lateral growth of nickel silicide.

Window size effect on lateral growth of nickel silicide in contact windows cut into oxide grown on Si (100) is studied. The growth rate is found to be independent of window size and follows the diffusion-limited process with activation energy of 1.5 eV. The Si erosions are observed to grow due to predominant Si diffusion for vacuum anneal above 600. This phenomenon becomes greatly pronounced with fine windows of 2 m in diameter. This phenomena can be attributed to (i) an enhanced stress level in fine windows causing reduction in the growth temperature of epitaxial NiSi2 in the windows and (ii) difference in surface energies of epitaxial NiSi2 formed and the Si substrate resulting in the shrinkage of the epitaxial NiSi2 dimension in the window. No such behavior is observed under identical conditions when Si(111) is used. This is due to the fact that the lateral growth of nickel silicide in this case is about a quarter of that for Ni-Si (100) lateral samples

A Photoemission Study.of the Influence of Sputtering on the Au-(Bi2212) Interface

X-ray photoemission measurements were performed on Au deposited on a Bi(2212) single crystal after progressively sputtering it with Ar ions. This was to see whether changes such as diffusion of Au, segregation of a particular element or clustering effects take place at the interface. Spectra of different core levels reveal no elemental diffusion at the interface and an absence of Au interaction with the crystal at room temperature