2001 Fiscal Year Annual Research Report

リラクサの高誘電率発生の機構解明

Research Project

Project/Area Number	12134202
Research Category	Grant-in-Aid for Scientific Research on Priority Areas (B)
Research Institution	Gifu University
Principal Investigator	安田直彦岐阜大学, 工学部, 教授 (90021625)
Co-Investigator(Kenkyū-buntansha)	大和英弘岐阜大学, 工学部, 助手 (70270973) 岩田真名古屋工業大学, 工学部, 助手 (40262886)
Keywords	リラクサ強誘電体 / 疲労効果の少ないFERAM / 高誘電率 / モルフォトロピック相境界 / ラマン散乱 / 電子線回折 / 電気光学応答 / エンジニアードドメイン構造
Research Abstract	リラクサ強誘電体及びそのPbTiO_3(PT)固溶体は、メモリーFERAMあるいはDRAMキャパシタ高誘電率薄膜等への応用が期待されている。これらの物質は、相転移温度近傍における誘電率のピークがブロードで温度係数が小さいこと、誘電率が著しく大きいこと、またそのモルフォトロピック相境界(MPB)で自発分極に垂直方向の不安定性のためメモリー等の特性が優れていることが理論的に石橋教授(1班)を含む本研究班により明らかにされて来ており、高いキュリ温度を有する単結晶材料のrhombohedral(100)板がFERAMに有用であることを指摘している。本研究班の目的は強誘電体薄膜素子に用いられる高誘電率物質リラクサ強誘電体における物性の解明や疲労効果の無いFERAMのデザインの提案である。本研究では、リラクサ強誘電体固溶体Pb(Zn_<1/3>Nb_<2/3>)O_3-PbTiO_3(PZN-PT)-Pb(Mg_<1/3>Nb_<2/3>O_3(PMN)Pb(In_<1/3>Nb_<2/3>)O_3-PbTiO_3(PIN-PT)を用いて、ラマン散乱、電子線回折、電気光学、ドメイン構造の変化の観測を行った。ラマン散乱と電子線回折の結果、PZNにおいて観測されるラマン活性モードの起源を明らかにし、また、PZN-PT混晶系の低周波数モードはPTにおけるソフトモードと同一の起源のモードであることが結論できた。電気光学応答測定の結果、リラクサ中には、不均一な歪場と誘電異方性があることが実験的に見出された。偏光顕微鏡を用いたドメインの構造変化を分極反転機構との関連に於いて調べ、分極反転ルートがrhombohedral(100)板の方がtetragonal(100)板に比べて、多肢に亘ることを実験的に明らかにし、分極が電極に垂直な角度からある角度ずれている方位の方がFERAMの疲労効果の少ないデザインであることを提案した。更に、自発分極に垂直方向の不安定性からリラクサの高誘電率発生のメカニズムについて議論した。

Research Products

(17 results)

All Other

All Publications (17 results)

[Publications] M.Iwata et al.: "Raman Scattering in the Pb(Zn_<1/3>Nb_<2/3>)O_3-PbTiO_3 Mixed Crystal System II"Jpn. J. Appl. Phys.. 40. 5819-5822 (2001)
[Publications] M.Iwata et al.: "A Raman Study of Phase Transitions in the Pb(Zn_<1/3>Nb_<2/3>)O_3-PbTiO_3 System"Ferroelectrics. 261. 83-88 (2001)
[Publications] N.Yasuda et al.: "Crystal growth and dielectric properties of solid solutions of Pb(Yb_<1/2>Nb_<1/2>)O_3 PbTiO_3 with a High Curie Temperature near"Jpn. J. Appl. Phys.. 40. 5664-5667 (2001)
[Publications] N.Yasuda et al.: "Crystal growth and electrical properties of lead indium niobate-lead titanate binary single crystal"J. Crystal Growth. 229. 229-304 (2001)
[Publications] H.Ohwa et al.: "Raman Scattering in (1-x)Pb(Mg_<1/3>Nb_<2/3>)O_3-xPbTiO_3"J. Phys. Soc. Jpn.. 70. 3149-3154 (2001)
[Publications] M.Iwata et al.: "Raman Scattering study in relaxor mixed crystals Pb(Zn_<1/3>Nb_<2/3>)O_3-PbTiO_3"Ferroelectrics. (2002)
[Publications] N.Yasuda et al.: "Dielectric and Piezoelectric Properties of Lead Indium Niobate-Lead Titanate Single Crystals with High Curie Temperature near Morphotropic Phase"Ferroelectrics. (2002)
[Publications] N.Yasuda et al.: "On Fatigue and Imprint in Engineered Domain Configurations For Lead-based Complex Perovskite Compounds with High Curie Temperature"1^<st> International Meeting on Ferroelectric Randam Access Memories. FED-175. 103-104 (2001)
[Publications] N.Yasuda, et al.: "Dielectric Properties of Lead Indium Niobate-Lead Titanate Single Crystals with High Curie Temperature near Morphotropic Phase Boundary"The 8^<th> Workshop on Oxide Electronics. 51 (2001)
[Publications] H.J.Fan et al.: "Brillouin and dielectric studies of the phase transition in the relaxor ferroelectric Pb(Ni_<1/3>Nb_<2/3>)O_3"J. Appl. Phys.. Vol.91 No.4. 2262-2266 (2002)
[Publications] Y.Yamashita et al.: "Present and Future of Piezoelectric Single Crystals and the Importance of B-site Cations for High Piezoelectric Response"IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control. Vol.49No.2. 184-192 (2002)
[Publications] M.Iwata et al.: "Hetero structure and electro-optic effect in relator Pb(Mg_<1/3>Nb_<2/3>)O_3"Trans. Mat. Res. Soc. Jpn.. (2002)
[Publications] Y.Ishibashi et al.: "On the Lattice Instability in Incommensurate Phase Transition of K_2SeO_4"J. Phys. Soc. Jpn.. 70. 3178-3179 (2001)
[Publications] M.H.Kuok et al.: "Hypersonic Frequency and Damping Anomalies in Relaxor Ferroelectric Pb(Zn_<1/3>Nb_<2/3>)O_3"Appl. Phys. Let.. 78. 1727-1729 (2001)
[Publications] M.H.Kuok et al.: "Hypersonic Frequency Softening and relaxation in Relaxor Ferroelectric 0.8Pb(Zn_<1/3>Nb_<2/3>)O_3-0.2PbTiO_3"Solid State Communications. 118. 169-172 (2001)
[Publications] M.Iwata et al.: "Theory of Morphotropic Phase Boundary in Solid Solution Systems of Perovskite-Type Oxide Ferroelectrics : Engineered Domain Configurations II"Jpn. J. Appl. Phys.. 40. 703-707 (2001)
[Publications] M.Iwata et al.: "A Theory of Polarization Reversals near the Morphotropic Phase Boundary of Perovskite-Type Oxide Ferroelectrics"Jpn. J. Appl. Phys.. 40. 708-712 (2001)

2001 Fiscal Year Annual Research Report

リラクサの高誘電率発生の機構解明

Principal Investigator

安田 直彦 岐阜大学, 工学部, 教授 (90021625)

Research Products

[Publications] M.Iwata et al.: "Raman Scattering in the Pb(Zn_<1/3>Nb_<2/3>)O_3-PbTiO_3 Mixed Crystal System II"Jpn. J. Appl. Phys.. 40. 5819-5822 (2001)

[Publications] M.Iwata et al.: "A Raman Study of Phase Transitions in the Pb(Zn_<1/3>Nb_<2/3>)O_3-PbTiO_3 System"Ferroelectrics. 261. 83-88 (2001)

[Publications] N.Yasuda et al.: "Crystal growth and dielectric properties of solid solutions of Pb(Yb_<1/2>Nb_<1/2>)O_3 PbTiO_3 with a High Curie Temperature near"Jpn. J. Appl. Phys.. 40. 5664-5667 (2001)

[Publications] N.Yasuda et al.: "Crystal growth and electrical properties of lead indium niobate-lead titanate binary single crystal"J. Crystal Growth. 229. 229-304 (2001)

[Publications] H.Ohwa et al.: "Raman Scattering in (1-x)Pb(Mg_<1/3>Nb_<2/3>)O_3-xPbTiO_3"J. Phys. Soc. Jpn.. 70. 3149-3154 (2001)

[Publications] M.Iwata et al.: "Raman Scattering study in relaxor mixed crystals Pb(Zn_<1/3>Nb_<2/3>)O_3-PbTiO_3"Ferroelectrics. (2002)

[Publications] N.Yasuda et al.: "Dielectric and Piezoelectric Properties of Lead Indium Niobate-Lead Titanate Single Crystals with High Curie Temperature near Morphotropic Phase"Ferroelectrics. (2002)

[Publications] N.Yasuda et al.: "On Fatigue and Imprint in Engineered Domain Configurations For Lead-based Complex Perovskite Compounds with High Curie Temperature"1^<st> International Meeting on Ferroelectric Randam Access Memories. FED-175. 103-104 (2001)

[Publications] N.Yasuda, et al.: "Dielectric Properties of Lead Indium Niobate-Lead Titanate Single Crystals with High Curie Temperature near Morphotropic Phase Boundary"The 8^<th> Workshop on Oxide Electronics. 51 (2001)

[Publications] H.J.Fan et al.: "Brillouin and dielectric studies of the phase transition in the relaxor ferroelectric Pb(Ni_<1/3>Nb_<2/3>)O_3"J. Appl. Phys.. Vol.91 No.4. 2262-2266 (2002)

[Publications] Y.Yamashita et al.: "Present and Future of Piezoelectric Single Crystals and the Importance of B-site Cations for High Piezoelectric Response"IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control. Vol.49No.2. 184-192 (2002)

[Publications] M.Iwata et al.: "Hetero structure and electro-optic effect in relator Pb(Mg_<1/3>Nb_<2/3>)O_3"Trans. Mat. Res. Soc. Jpn.. (2002)

[Publications] Y.Ishibashi et al.: "On the Lattice Instability in Incommensurate Phase Transition of K_2SeO_4"J. Phys. Soc. Jpn.. 70. 3178-3179 (2001)

[Publications] M.H.Kuok et al.: "Hypersonic Frequency and Damping Anomalies in Relaxor Ferroelectric Pb(Zn_<1/3>Nb_<2/3>)O_3"Appl. Phys. Let.. 78. 1727-1729 (2001)

[Publications] M.H.Kuok et al.: "Hypersonic Frequency Softening and relaxation in Relaxor Ferroelectric 0.8Pb(Zn_<1/3>Nb_<2/3>)O_3-0.2PbTiO_3"Solid State Communications. 118. 169-172 (2001)

[Publications] M.Iwata et al.: "Theory of Morphotropic Phase Boundary in Solid Solution Systems of Perovskite-Type Oxide Ferroelectrics : Engineered Domain Configurations II"Jpn. J. Appl. Phys.. 40. 703-707 (2001)

[Publications] M.Iwata et al.: "A Theory of Polarization Reversals near the Morphotropic Phase Boundary of Perovskite-Type Oxide Ferroelectrics"Jpn. J. Appl. Phys.. 40. 708-712 (2001)

安田直彦岐阜大学, 工学部, 教授 (90021625)