Real Information Recording in Ferroelectric Data Storage Medium with Memory Density of 1 Tbit/inch 2
- PDF / 2,488,628 Bytes
- 6 Pages / 595 x 842 pts (A4) Page_size
- 65 Downloads / 177 Views
0902-T10-41.1
Real Information Recording in Ferroelectric Data Storage Medium with Memory Density of 1 Tbit/inch2 K. Tanaka, Y. Hiranaga and Y. Cho Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
Abstract In this study, a new method to achieve real information recording with a density of 1 Tbit/inch2 in ferroelectric data storage systems is proposed. In this system, data bits were written in the form of the polarization direction of nano domains. Local domain switching was carried out by applying a voltage pulse. A series of test writes revealed that the bit size varied according to the polarization direction of the bits in the immediate environment. Therefore, in order to keep the bit size constant (at 25.6 nm), the pulse amplitude required to create each individual bit was calculated as a function of the polarities of the surrounding data bits. As a result, real information storage at a density of 1 Tbit/inch2 was successfully achieved, with a low bit error rate of 1.8 × 10-2.
Introduction With the advance of information processing technology, the importance of high-density data storage is increasing. Magnetic storage plays the main role in this field, however this technology has serious problems in terms of ultra high-density recording. With these backgrounds, we have proposed ferroelectric data storage system. This system is suitable for high-density storage because the domain wall thickness of a typical ferroelectric material is of the order of only a few lattice spacings [1]. For this system, the read/write technique used is based on Scanning Nonlinear Dielectric Microscopy (SNDM)[2]-[4]. This has a great advantage over other methods in bit detection resolution. In ferroelectric data storage, the polarization directions act as data bits of ‘1’ and ‘0’. Previously, a simple uniform inverted nano domain dot array with a density of 10.1 Tbit/inch2 has been successfully written on a Congruent Single Crystal LiTaO3(CLT) thin plate [3]. However, real information data has not yet been recorded with a density of 1 Tbit/inch2, because real information is complex and non-uniform and so is difficult to write successfully. In this study, the successful writing of real information data at a density of 1 Tbit/inch2 is described and a bit error reduction method is discussed. After several experiments, it was determined that the appropriate value of domain switching pulse voltage depends on the polarization directions in the immediate environment. Therefore, to improve bit error rate (BER),
0902-T10-41.2
the pulse voltage was varied based on the polarization directions in the immediate environment. As a result, actual information data was successfully written with a density of 1 Tbit/inch2 and with a low BER.
Experimental Setup SNDM is the first successful purely electrical method for observing ferroelectric polarization distribution at sub-nanometer resolution [6][7]. In order to determine polarization direction, the lowest order nonlinear dielectric
Data Loading...
