Browsing by Author "LIN, IN"

Now showing 1 - 4 of 4

GROWTH AND FERROELECTRICITY OF EPITAXIAL-LIKE BATIO3 FILMS ON SINGLE-CRYSTAL MGO, SRTIO3, AND SILICON SUBSTRATES SYNTHESIZED BY PULSED-LASER DEPOSITION
(1995-06-15)
LIN, WJ
;
TSENG, TY
;
LU, HB
;
TU, SL
;
YANG, SJ
GROWTH OF EPITAXIAL-LIKE (SR0.5BA0.5)NB2O6 FERROELECTRIC-FILMS
(1995-05-15)
LIN, WJ
;
TSENG, TY
;
LIN, SP
;
TU, SL
;
YANG, SJ
Epitaxial-like (Sr0.5Ba0.5)Nb2O6 (SBN) films were successfully grown on (100) silicon substrates, using [002] CeO2 as the buffer layer and [001]YBa2Cu3O7-x (YBCO) as the base electrode. The theta-2 theta scan and phi-scan X-ray diffraction suggest that [210](SBN)//[100](YBCO)//[110]CeO2//[110](si). The ferroelectric hysteresis curves measured by the modified Sawyer-Tower technique show that the epitaxial-like SBN/YBCO/CeO2/Si films possess substantially better ferroelectricity than the polycrystalline SBN/Pt(Ti)/Si films. The remanent polarization (P-r) and coercive field (E(c)) are, respectively, P-r = 27.2 mu C/cm(2) and E(c) = 24.8 kV/cm.
GROWTH-BEHAVIOR OF Y1BA2CU3O7-X SUPERCONDUCTING THIN-FILMS USING LASER-ABLATION TECHNIQUE
(1994-07-01)
HUANG, CS
;
LIN, IN
;
LEE, JYM
;
TSENG, TY
;
電子工程學系及電子研究所
The growth behavior of Y1Ba2Cu3O7-x (YBCO) thin films on MgO substrates synthesized by laser ablation deposition techniques has been investigated. The effects of important parameters, i.e., substrate temperature, post annealing schemes, laser beam fluence and deposition chamber atmosphere on the crystal structure, microstructure and superconductivity of the deposited films have been studied. Among those important depositing parameters, the plume to film interaction was observed to impose the most prominent effect on the film characteristics. The films were found to consist mainly of a noncrystalline phase whenever the substrates were located either in the invisible or the supersonic zones of the plume. Only when the substrates are positioned in the reactive zone does the crystalline phase grow rapidly via a nucleation and growth mechanism. The (013) grains nucleate preferentially and are subsequently transformed into a (00m) orientation, possibly by diffusion. The number of (013) grains transformed increases with temperature used for step annealing and with time at that temperature.
ORIENTATION-DEPENDENT X-RAY ABSORPTION FINE-STRUCTURE (XAFS) OF THE BI-SR-CA-CU-O SYSTEM
(1992-12-01)
CHOU, CH
;
PONG, WF
;
SHI, JB
;
KU, HC
;
LIN, IN
Using the transmission and fluorescence modes at the National Synchrotron Light Source (NSLS) X-23A2 beam line, we have measured polarized XAFS spectra of the Bi, Pb L3-edges and the Cu K-edge for the (Bi1.85Pb0.15)Ca2.2Sr1.8Cu3O10+delta sample and unpolarized XAFS spectra of the Bi, Pb L3-edges and the Cu K-edge for Bi2Ca1.2Sr1.8Cu2O8+delta, Pb0.2Bi1.9Sr1.9Cu1O6+delta and (PbxBi2-x)Sr2Ca2Cu3Oy (x = 0, 0.2, 0.4) samples. All XAFS spectra were measured at room temperature. The incommensurate modulations in the Bi-O layers are discussed in terms of the XAFS technique. The XAFS spectra of Bi L3-edge do not vary substantially for different sample orientation with respect to the X-ray polarization vector E. There is evidence for the existence within the Bi-Sr-Ca-Cu-O system of Bi atoms having the oxidation number exceeding 3. Pb ions predominantly substitute for Bi ions in the Bi-Sr-Ca-Cu-O system because there is no significant difference between the XANES spectra of the Pb and Bi L3-edges, respectively. The oxidation numbers of substituted Pb in Bi-Sr-Ca-Cu-O system differ much from those of Pb in PbO2 in which the oxidation number of all Pb atoms is 4. In agreement with other investigators, our results on the polarized XANES spectra of the Cu K-edge indicate that a satellite about 7 eV above the main K-XANES peak in both polarizations is a multielectron excitation to the final-state configuration 1s3d9epsilonp1, and that a shoulder on the rising absorption edge, present for many Cu compounds and generally assigned to a shake-down multielectron excitation, is a transition to a final state of the Cu compounds. We have also deduced that the structure of the Cu-O planes in the Bi-Sr-Ca-Cu-O samples is ordered.