| Project/Area Number |
15206036
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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 |
Electron device/Electronic equipment
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| Research Institution | Tohoku University |
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Principal Investigator |
CHO Yasuo Tohoku University, Research Institute of Electrical Communication, Professor, 電気通信研究所, 教授 (40179966)
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| Co-Investigator(Kenkyū-buntansha) |
OHARA Koya Tohoku University, Research Institute of Electrical Communication, Research Associate, 電気通信研究所, 助手 (70400421)
小田川 裕之 東北大学, 大学院・工学研究科, 助教授 (00250845)
森田 剛 東北大学, 電気通信研究所, 助手 (60344735)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥49,660,000 (Direct Cost: ¥38,200,000、Indirect Cost: ¥11,460,000)
Fiscal Year 2005: ¥14,040,000 (Direct Cost: ¥10,800,000、Indirect Cost: ¥3,240,000)
Fiscal Year 2004: ¥17,420,000 (Direct Cost: ¥13,400,000、Indirect Cost: ¥4,020,000)
Fiscal Year 2003: ¥18,200,000 (Direct Cost: ¥14,000,000、Indirect Cost: ¥4,200,000)
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| Keywords | scanning nonlinear dielectric microscopy / ferroelectrics / domain / SPM / data storage / super high density data storage / 強誘電体記 |
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| Research Abstract |
Ferroelectrics can hold bit information in the form of the polarization directions of individual domains. Moreover, the domain walls of typical ferroelectric materials are as thin as of the order of a few lattice parameters, which is favorable for high density data storage. Therefore, we have studied ferroelectric high density data storage based on scanning non-linear dielectric microscopy (SNDM) and using LiTaO_3 (CLT) single-crystal thin plate as a recording medium.
In this study, considerable progress has been made towards the realization of ferroelectric technology for data storage using SNDM and a CLT thin plate. First we performed fundamental studies on the highest memory density and fastest switching speed in ferroelectric data storage and succeeded in forming our smallest artificial nanodomain single dot at 5.1nm diameter and then forming a nanodomain dot array with an areal density of 10.1Tbit/inch^2. A subnanosecond (500ps) domain switching speed was also successfully achieved. Next, actual information storage with a low bit error and high memory density was performed. As a result, a bit error ratio (BER) of less than 1 × 10^<-4> was achieved at an areal density of 258Gbit/inch^2. Moreover, a data bit array of 128 × 82 was successfully written at an areal data storage density of 1Tbit/inch^2 with a bit error rate of 1.8 × 10^<-2>. Finally we also investigated long term retention characteristic of nanodomain dots formed in CLT and obtained results that the formed nanodomain dot last at least for ten years at 80℃.
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