Selection of the best proper DC-SQUIDs in a multi-SQUID configuration

We have carried out experimental investigation of multi-DC-SQUID magnetometer configuration fabricated on YBa2Cu30 7-δ thin films onto 24 degree SrTiO3 bicrystal substrates by directly coupling the pick-up loop to DC-SQUIDs. The layout of the magnetometer pick-up loop was chosen as a square washer configuration by maximizing loop effective area and minimizing loop inductance. We have used De-Magnetron Sputtering technique for deposition of the films and chemical etching process for patterning the Josephson junctions having 4 μm widths. The use of multi-SQUID configuration is related to the selection of the best proper junctions for SQUID to improve the chip sensitivity with selectivity option of choosing the squid junctions rather than multichannel operation. Selection of the best junctions compared to each other depending on the junction critical currents and noise levels caused by the fabrication process and placements of the junctions on the grain boundary enable having an increased output signal of the DC-SQUID. © 2007 IEEE

The superconducting transition width and illumination wavelength dependence of the response of MgO substrate YBCO transition edge bolometers

Dependence of the phase and magnitude of the response of MgO substrate YBa2Cu3O7-δ (YBCO) transition edge bolometers to the near infrared radiation on the superconducting transition width is presented in this work. The bolometers were made of YBCO thin films of 200 nm thickness that were grown on single crystal MgO (1 0 0) substrates by DC inverted cylindrical magnetron sputtering. We have measured the responses of both large and small area devices with respect to the bias temperature and radiation modulation frequency. We have observed that the superconducting transition width has major effects on the response of the bolometers such as; on a dip of the phase of the response versus modulation frequency curve around 1 Hz, the rate of decrease of the magnitude of the response, and dependence of the phase of the response on temperature at mid-range modulation frequency. We have investigated a correlation between the superconducting transition width and the YBCO film surface morphology of the devices. In addition, the illumination wavelength dependence of the optical response of both wide and narrow transition width devices has been investigated. Here we present the analysis and the possible mechanisms that can affect the response of the bolometers at the superconducting transition region. © 2007 Elsevier B.V. All rights reserved

Dependence of Josephson junction critical current on the deposition rate of YBa2Cu3O7-δ thin films

We have reported the effect of YBa2Cu3O 7-δ (YBCO) thin film deposition rate on the 24 and 30 degree STO bicrystal Josephson junctions critical currents by fabricating series of junctions with different deposition rates. Dependence of YBCO thin film structures on the deposition rate was investigated. We have observed that the critical currents of junctions are strongly affected by the thin film deposition rate. © 2007 American Institute of Physics

The effect of vanadium doping on superconducting properties of (Bi, Pb)2Sr2Ca2(Cu1-xVx) 3O? ceramics

We report on the studies of doping vanadium with (Bi, Pb)2Sr2Ca2 (Cu1-x,Vx)3O?, at low concentration of x = 0.01-0.03. The superconductivity of the samples were determined by employing a.c. resistivity, a.c. susceptibility and X-ray diffraction measurements. For the low concentration range of vanadium we have observed some enhancement effects in stabilizing the high Tc phase, resulting in increase in the volume fraction of it. The role of the presence of two additives in BiSrCaCuO system is discussed in modifying the superconductivity of this system. © 1998 Elsevier Science Ltd. All rights reserved

A study on the effect of Ni doping on Bi - Pb - Sr - Ca - Cu - O system

The effect of Ni doping on superconductivity properties of the Bi1.7Pb0.3Sr2Ca2(Cu 1-xNix)3Oy system has been investigated by means of x-ray diffraction, ac electrical resistance, ac magnetic susceptibility and critical current measurements. The volume fraction of the 2223 phase decreases with increasing Ni concentration. The zero-resistance temperature and the critical current density are suppressed with Ni substitution

The effects of the post-annealing temperature on the growth mechanism of Bi2Sr2Ca1Cu2O8+ ? thin films produced on MgO (1 0 0) single crystal substrates by pulsed laser deposition (PLD)

The effects of post-annealing temperature were investigated on Bi 2Sr2Ca1Cu2O8+ ? thin films deposited on MgO (1 0 0) substrates by pulsed laser deposition (PLD). The structural and superconducting properties of the films have been determined by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature dependent resistivity (R-T), and DC magnetization measurements. The films which were deposited at 600 C were post-annealed in an atmosphere of a gas mixture of Ar (93%) and O2 (7%), at temperature ranging between 800 and 880 C. This resulted in films which exhibited a single phase of 2212 with a high crystallinity (FWHM ? 0.16) and texturing along the c-axis, perpendicular to the plane of the substrate. An optimum temperature of 860 C was found for the post-annealing thermal treatment. The critical temperature, TC, of the films was measured as 82 K and the critical current density, JC, was calculated as 3 × 107 A/cm2 for the film annealed at 860 C. © 2013 Elsevier B.V. All rights reserved.This work is supported by Research Fund of Cukurova University , Adana, Turkey, under Grant No. FEF2011D20 . The authors gratefully acknowledge the Material Research Center of Izmir Institute of Technology, for their kind help and to the staff members of the Pulsed Laser Deposition Laboratory for the preparation and analysis of our films

Effect of deposition conditions on YBa2Cu3O7-delta thin films by inverted cylindrical magnetron sputtering and substrate effects

WOS: 000220890500014The dependence of YBCO thin film properties on the deposition conditions was studied for different substrates. The deposition conditions were optimized for the epitaxial growth of high quality YBCO thin films of 1500 A thickness onto single crystal (100-oriented) SrTiO3 (STO), MgO and LaAlO3 (LAO) substrates by DC Inverted Cylindrical Magnetron Sputtering (ICMS). The samples were investigated in detail by means of X-ray diffraction analysis (XRD), EDX, AFM, rho-T, magnetic susceptibility and current-voltage (I-V) characterizations. The samples show strong diamagnetic behavior and sharp transition temperatures of 89-91 K with DeltaT < 0.5 K. XRD of the samples exhibited highly c-axis orientation. The full width at half maximum (FWHM) values of the rocking curves were ranging typically from 0.22 to 0.28degrees. The samples have smooth surfaces as shown from AFM micrographs. The surface roughness, R-a, changed between 5-7 nm. I-V characteristics were obtained from the 20 mum-wide microbridges, which were patterned by a laser writing technique. The critical current densities (J(c), 1.06 X 10(6) for LAO-based YBCO, 1.39 X 10(6) for MgO-based YBCO, 1.67 X 10(6) A/cm(2) for STO based YBCO) of the microbridges were evaluated from I-V curves at 77 K. (C) 2004 Published by Elsevier Ltd

The effects of the post-annealing time on the growth mechanism of Bi(2)Sr(2)CalCu(2)O(8-partial derivative) thin films produced on MgO (100) single crystal substrates by pulsed laser deposition (PLD)

WOS: 000370884500025Bi(2)Sr(2)CalCu(2)O(8+partial derivative) thin films were deposited on MgO (100) substrates by pulsed laser deposition (PLD). The effects of post-annealing time on the phase formation, the structural and superconducting properties of the films have been investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature dependent resistivity (R-T), atomic force microscopy (AFM), and DC magnetization measurements. The films deposited at 600 degrees C were post-annealed in an atmosphere of a gas mixture of Ar (93%) and O-2 (7%), at 860 degrees C for 10, 30, and 60 min. All films have demonstrated a mainly single phase of 2212 with a high crystallinity (FWHM approximate to 0.159 degrees) and c-axis oriented. The critical temperature, T-C, of the films annealed for 10, 30, and 60 min were obtained as 77, 78, and 78 K, respectively. The highest critical current density, J(C), was calculated as 3.34 x 10(7) A/cm(2) for the film annealed at 860 degrees C for 30 min at 10 K. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.Research Fund of Cukurova University, Adana, TurkeyCukurova University [FEF2011D20]This work is supported by Research Fund of Cukurova University, Adana, Turkey, under Grant no: FEF2011D20. The authors gratefully acknowledge the Material Research Center of Izmir Institute of Technology, for their kind help and to the staff members of the Pulsed Laser Deposition Laboratory for the preparation and analysis of our films

The effects of the post-annealing time on the growth mechanism of Bi2Sr2Ca1Cu2O8+ thin films produced on MgO (100) single crystal substrates by pulsed laser deposition (PLD)

Bi2Sr2Ca1Cu2O8+?ï thin films were deposited on MgO (100) substrates by pulsed laser deposition (PLD). The effects of post-annealing time on the phase formation, the structural and superconducting properties of the films have been investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature dependent resistivity (R-T), atomic force microscopy (AFM), and DC magnetization measurements. The films deposited at 600 °C were post-annealed in an atmosphere of a gas mixture of Ar (93%) and O2 (7%), at 860 °C for 10, 30, and 60 min. All films have demonstrated a mainly single phase of 2212 with a high crystallinity (FWHM0.159°) and c-axis oriented. The critical temperature, TC, of the films annealed for 10, 30, and 60 min were obtained as 77, 78, and 78 K, respectively. The highest critical current density, JC, was calculated as 3.34×107 A/cm2 for the film annealed at 860 °C for 30 min at 10 K. © 2016 Elsevier Ltd and Techna Group S.r.l.FEF2011D20This work is supported by Research Fund of Cukurova University , Adana, Turkey, under Grant no: FEF2011D20 . The authors gratefully acknowledge the Material Research Center of Izmir Institute of Technology, for their kind help and to the staff members of the Pulsed Laser Deposition Laboratory for the preparation and analysis of our films