| Budget Amount *help |
¥7,100,000 (Direct Cost: ¥7,100,000)
Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1986: ¥6,600,000 (Direct Cost: ¥6,600,000)
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| Research Abstract |
The purpose of this study is to clarify the structures and binding states and the distrubution of dopants of the conducting polymer, polypyrrole(PP), and the effect of oxidation fully utilizing the unique capability of the atom-probe(A-P). Usefulness of the ultramicroanalysis of high temperature superconducting ceramics with A-P was examined.
A-P specimens are fine needles with a tip radius of less than 1000<ang>. Since it is not easy to make a sharp polymer tip, a thin PP film was fablicated on a Pt tip by electrochemically polymerizing pyrrole. The dopants to make PP conductive are ClO_4^- and BF_4^-. PP-metal interfaces were formed by depositing a metal film in the UHV A-P.
The distribution of cluster ions detected by the A-P mass analysis indicates that an oxgen atom breaks in a C-H bond of PP and then release H forming a stable C=O double bond. The thickness of the fully oxidized PP film is approximately 500<ang> after 3 month exposure to air. The Cl atoms dpoed in PP were not detected possibly due to its high vapor pressure. On the contrary, boron with the high melting temperature migrates away from the oxidezed regions of PP by the repulsive B-O interaction and is detected from the non-oxidized PP.
Al^+, Ag^+, AlO^+ and AgO^+ were detected from the Al, Ag or In films deposited on PP but In was detected with various oxidized PP fragments, such as In-Co^+, In-C _2O_2^+ and In-C_2 NO^+.
In order to explain the superconduction mechanism of high Tc ceramics, a new model has been proposed. In this model, extra oxygen atoms absorbed on the ceramic surface draw electronic charge from the oxygen atoms of the Cu-O network of the ceramics. Then, the induced lone pair orbitals of the network oxygen are electronically polarized and interactwith the conduction electrons and generate the inter-electron attractive force and the Cooper pairs which make the ceramics superconductive.
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