• Article  

      Anisotropy of the resistivity in the a-b plane of a superconducting YBa2Cu3O7-δ single crystal 

      Kim, J.-T.; Giapintzakis, John; Ginsberg, D. M. (1996)
      We have measured the in-plane longitudinal resistivities pa and pb as functions of temperature and magnetic field. The measurements were all made on the same detwinned single crystal of YBa2Cu3O7-δ (YBCO). Defining Tc to ...
    • Conference Object  

      ARPES studies of the superconducting gap in high-temperature superconductors 

      Ding, H.; Norman, M. R.; Giapintzakis, John; Campuzano, Juan C.; Claus, H.; Wuehl, H.; Randeria, M.; Bellman, A.; Yokoya, T.; Takahashi, T.; Mochiku, T.; Kadowaki, Kazuo; Ginsberg, Don M. (Affiliation: Argonne Natl. Lab. and Univ. of, Illinois/Chicago, Chicago, IL, USA, United StatesCorrespondence Address: Ding, H.Argonne Natl. Lab. and Univ. of, Illinois/Chicago, Chicago, IL, USAUnited States, 1996)
      Using high resolution angle-resolved photoemission spectroscopy (ARPES), we measure the superconducting gap and its momentum dependence in the high temperature superconductors Bi 2Sr 2CaCu 2O 8 (Bi2212) and YBa 2Cu 3O 6.95 ...
    • Article  

      C-axis josephson tunneling between YBa2Cu3O7 − δ and Pb: Direct evidence for mixed order parameter symmetry in a high- Tc superconductor 

      Kouznetsov, K. A.; Sun, A. G.; Chen, B.; Katz, A. S.; Bahcall, S. R.; Clarke, J.; Dynes, R. C.; Gajewski, D. A.; Han, S. H.; Maple, M. B.; Giapintzakis, John; Kim, J.-T.; Ginsberg, T. M. (1997)
      C-axis Josephson tunneling experiments in which a conventional superconductor (Pb) is deposited across a single twin boundary of a YBa2Cu3O7 − δ (YBCO) crystal. We measure the critical current as a function of the magnitude ...
    • Article  

      Disorder-induced vortex phase transition in untwinned YBa2Cu3O7-δ crystal 

      Giller, D.; Giapintzakis, John; Shaulov, A.; Yeshurun, Y. (2000)
      Local magnetic measurements in an untwinned YBa2Cu3O7-δ crystal as a function of temperature, field and time reveal anomalies occurring along the same line BSS(T) in the field-temperature plane. We identify BSS(T) as a ...
    • Article  

      Hall effect in detwinned single crystals of YBa2(Cu1-xZnx)3O7-δ in the mixed state 

      Schegolev, A. I.; Giapintzakis, John; Manson, J. T.; Ginsberg, D. M.; Dumler, I. (1996)
      The effect of zinc doping on the mixed-state Hall effect in detwinned single crystals of YBa2Cu3O7-δ has been studied. We observe a sign reveral of the Hall effect in crystals with a superconducting transition temperature ...
    • Article  

      Photothermal measurements of differential reflectivity of YBCO related to the symmetry of the superconducting order parameter 

      Fishman, I. M.; Studenmund, W. R.; Kino, G. S.; Giapintzakis, John (1996)
      We have investigated symmetry of the differential optical response of single YBCO domains in the a-b plane. As a function of temperature, this response consists of a smooth background and a sharp peak in the vicinity of ...
    • Article  

      Progress in photothermal microscopy of YBa2Cu3O7-x 

      Studenmund, W. R.; Fishman, I. M.; Kino, G. S.; Giapintzakis, John (1998)
      We present recent differential optical reflectivity (DOR) measurements obtained at 633 nm (2.OeV), 780 nm (1.6eV), 1064 nm (1.16eV), and 1310nm (0.95 eV). We discuss calibration techniques which can correct for variations ...
    • Article  

      Sign reversal of the Hall effect in YBa2(Cu1-x)3O7-δ single crystals 

      Neiman, R. L.; Giapintzakis, John; Ginsberg, D. M.; Mochel, J. M. (1995)
      We have measured the in-plane Hall effect and in-plane resistivity of cobalt-doped YBa2Cu3O7-δ (YBCO) single-crystal samples. The concentration of cobalt ranged from 1 to 3%. As the applied field was varied, a sign reversal ...
    • Article  

      Spin-gap and antiferromagnetic correlations in low-dimensional PbNi2-xAxV2O8 compounds (A = Mg, Co) 

      Mastoraki, I.; Lappas, A.; Schneider, R.; Giapintzakis, John (2002)
      The effect of the impurity doping in the quantum-spin chains of the PbNi2V2O8 Haldane-gap compound is studied. We report elastic neutron scattering and bulk magnetic susceptibility measurements on the quasi-one-dimensional ...
    • Article  

      Tunneling in Pb-YBCO junctions: Determining the symmetry of the pairing state 

      Wollman, D. A.; Harlingen, D. J. Van; Giapintzakis, John; Ginsberg, D. M. (1995)
      We report on our efforts to understand the origin of supercurrent observed in c-axis tunnel junctions on YBCO [Sun A. G. et al., Phys. Rev. Lett. 72, 2267 (1994).] by studying the phase coherence of a-axis/c-axis and ...