2005 Fiscal Year Final Research Report Summary
Structure control in atomic scale of relaxors with morphotropic phase boundary composition
| Project/Area Number |
14204031
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体物性Ⅰ(光物性・半導体・誘電体)
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| Research Institution | Waseda University |
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Principal Investigator |
UESU Yoshiaki Waseda Unversity, Faculty of Science & Engineering, Prof, 理工学術院, 教授 (10063744)
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| Project Period (FY) |
2002 – 2005
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| Keywords | Relaxor / Perovskite oxide / Pulse-laser deposition method / Thin films / Morphotropic phase boundary / Dielectric constant / Electric-field-induced resistant switching |
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| Research Abstract |
(1)Syntheses of super lattice thin films of Pb(Sc1/2Nb1/2)O3/PbTiO3 and dielectric properties
Highly oriented Pb(Sc_<1/2>Nb_<1/2>)O_3 (PSN) and PbTiO_3 (PT) super-lattice thin films are synthesized on single-stepped SrTiO_3 (001) substrates by pulsed laser deposition (PLD) technique. SrRuO_3 is deposited on the substrate as a bottom electrode layer for dielectric measurements. The orientation and structure of the films are checked by X-ray diffraction (XRD) method. Clear super-lattice reflections are observed by XRD and the period of super-lattice, the correlation length and the mosaicity are calculated from XRD profiles of the super-lattice. Real part of the dielectric constant is about 350 at room temperature in the frequency range of 102〜105 Hz.
(2)Electric-field-induced resistance switching observed in transition-metal-oxide thin films
We show that polarity-dependent, nonvolatile resistance switching by electric field occurs in the thin film of various transition-metal oxides in almost the same manner. This result indicates that contrary to the general acceptance, perovskite manganite is by no means a special compound for this phenomenon. It is also suggested that the resistance switching is not dominated by a detailed electronic structure of each sample, but dominated by a more general origin, e.g., crystalline defect.
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