Browsing by Author "Chin, CC"

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Anisotropic characteristics of in-plane aligned a-axis YBa2Cu3O7-delta thin films
(2003-05-01)
Luo, CW
;
Chen, MH
;
Chin, CC
;
Wu, KH
;
Juang, JY
Highly in-plane aligned a-axis oriented YBa2Cu3O7-delta (YBCO) thin films with unprecedented transition temperature (T-c similar to 91.3 K) have been deposited on (100) LaSrGaO4 substrates using a continuously grown PrBa2Cu3O7-delta (PBCO) template layer by pulsed laser. The anisotropies between b- and c-axis were investigated by transport measurements and atomic force microscopy (AFM). Although, the onset T-c's along b- and c-axis appeared approximately the same, a significant filing was observed in the resistive transition along c-axis. The temperature-dependent of the tailing effect, however, cannot be explained by thermally activated phase-slippage (TAPS) commonly encountered in grain-boundary weak links.
On the off stoichiometry of cerium oxide thin films deposited by RF sputtering
(1996-04-01)
Chin, CC
;
Lin, RJ
;
Yu, YC
;
Wang, CW
;
Lin, EK
We have studied the stoichiometry of cerium oxide films deposited by RF sputtering as a function of deposition conditions using the resonant Rutherford backscattering method. We found that some films have an off-stoichiometry of CeOy with y greater than 2.0. Such an off-stoichiometry cannot be due to a mixture of the known phases of bulk cerium oxide samples. Those thin samples may have either cerium vacancies or interstitial oxygen atomic impurities. We have tried to determine the valence of the cerium ions by measuring the X-ray photoemission.
Resonant rutherford backscattering studies of cerium oxide thin films deposited by RF sputtering
(1997-06-01)
Chin, CC
;
Lin, RJ
;
Yu, YC
;
Wang, CW
;
Lin, EK
We have studied the stoichiometry of cerium oxide films deposited by RF sputtering on sapphire and MgO as a function of deposition conditions using the resonant Rutherford backscattering method. We found that some films have the off-stoichiometry of CeOy with y greater than 2.0. Such an off-stoichiometry cannot be due to a mixture of the known phases of bulk cerium oxide samples. This may be due to either cerium vacancies or interstitial oxygen atomic impurities. The cerium ion x-ray photoemission spectra of those films cannot determine the vacancy of the cerium ions. The c-axis YBaCuo thin flims deposited by sputtering on the CeO3.3 buffer layer on saphhire was found to be epitaxial. The T-c was 86 K with Delta T-c less than 1 K.