Browsing by Author "HAUNG, CJ"

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BOLOMETRIC RESPONSE OF SUPERCONDUCTING YBA2CU3O7-X MICROBRIDGES
(1992-12-15)
HAUNG, CJ
;
CHANG, CY
;
TSENG, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The optical properties of superconducting bolometers have been presented in YBa2Cu3O7-x epitaxial films irradiated by a light emission diode with an 0.94 mum wavelength. The better response occurring in the resistive transition region has been shown and studied. A thermal fluctuation on the flux creep behavior can be employed to illustrate the nonlinearity optical current-voltage (I-V) characteristics in the low-resistive region. However, a dissipative mechanism of flux flow should be used in explaining the best response that reveals a linear I-V relation. Measurement of the bridges yielded the bolometric responsivity of approximately 77 V/W, by illuminating a 2 Hz dynamic signal with 0.15 mW. The noise equivalent power has been estimated as 3.2 X 10(-10) W Hz-0.5.
BOLOMETRIC YBA2CU3O7-X INFRARED DETECTOR
(1991-09-12)
TSENG, TY
;
CHANG, CY
;
HAUNG, CJ
;
CHEN, MC
;
電子工程學系及電子研究所
Results of the measurement of optical detection in YBa2Cu3O7-x superconducting epitaxial films at a wavelength of 0.94-mu-m are presented. These films show bolometric responses at temperatures in the resistive transition regions which are strongly dependent on the bias current. For 0.94-mu-m radiation, electronically chopped at 20 Hz, measurement of a meander bridge yields a bolometric responsivity of approximately 6.1 V/W.
FLUX MOTION DEPENDENCE OF RESISTIVE PROPERTIES IN SUPERCONDUCTING YBA2CU3O7-X THIN-FILMS
(1992-08-01)
HAUNG, CJ
;
CHEN, YC
;
TSENG, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Two models of flux motion are employed to study the resistive properties of superconducting YBa2Cu3O7-x thin films. The thermally activated flux creep model is employed to explain the dissipative behavior in the low resistivity region. However, when the resistivity is raised and approaches the normal state resistivity, the dissipative mechanism is gradually transferred from flux creep to flux flow. Based on the flux flow model, the upper critical field is estimated and shown as a function of temperature. In addition, a parallel resistivity circuit model is proposed to describe the transition behavior of the magnetic field dependence of resistivity versus current density characteristics.
INSITU GROWTH OF SUPERCONDUCTING YBA2CU3O7-X THIN-FILMS
(1991-09-01)
HAUNG, CJ
;
CHANG, CY
;
CHEN, MC
;
TSENG, TY
;
電子工程學系及電子研究所
Using single-target on-axis sputter deposition, YBa2Cu3O7-x films, with flatness oriented in the c axis and a zero-resistance temperature (T(co)) of 89 K, were prepared by an in situ growth technique. This work examines the effect of the growth temperature on the properties of in situ films. The experimental results show that high-quality YBa2Cu3O7-x films can be obtained by controlling the substrate temperature in a range from 680-degrees to 690-degrees-C. In addition, a new parallel-circuit model is proposed and a simulation of the resistance versus temperature curve is presented.
SUPERCONDUCTING PROPERTIES OF ORIENTED YBA2CU3O7-X FILMS ON MGO AND SRTIO3 SUBSTRATES
(1993-05-01)
HAUNG, CJ
;
TSENG, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Using single-target sputter deposition, the c-axis oriented YBa2Cu3O7-x films can be obtained on both MgO and SrTiO3 substrates by appropriately controlling the substrate temperature at 700-degrees-C. However, on examining a.c. susceptibility and electrical dissipation, we find that the films on a SrTiO3 substrate possess better superconducting properties, such as a stronger coupling between the superconducting grains; a higher potential energy for flux pinning; and a larger capacity for current conduction. Also, from the magnetization hysteresis measurement, the critical current density of 2.6 x 10(6) A cm-2 (77 K) and 4.5 x 10(7) A cm-2 (5 K) for the sample on the SrTiO3 substrate can be estimated.
TRANSITION PHENOMENA OF YBA2CU3O7-X THIN-FILMS ON MGO AND SRTIO3 SUBSTRATES
(1991-12-01)
HAUNG, CJ
;
CHEN, YC
;
TSENG, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The superconducting YBa2Cu3O7-x thin films were prepared by an in-situ DC sputtering system. The superconducting transition of the films in magnetic fields, applied parallel to the c-axis, was studied experimentally. Arrhenius plots of the resistivity data have shown that the dissipative flux motion of these samples could be explained by the thermally activated mechanism. In addition, we also found that the film on MgO substrate reveals a linear I-V curve, while the film on SrTiO3 substrate shows a nonlinear behavior. The relation between the activation energy and I-V behavior of the films on different substrates is also discussed.
ZERO RESISTANCE AT 125-K IN BI(PB)-SR-CA-CU-O SUPERCONDUCTOR
(1989-11-01)
HAUNG, CJ
;
TSENG, TY
;
HEH, TS
;
CHEN, FH
;
JONG, WS