Ultrahigh-density ferroelectric data storage based on scanning nonlinear dielectric microscopy

Ferroelectrics have generated considerable interest as promising storage media. In this paper, an investigation of ultrahigh-density ferroelectric data storage based on scanning nonlinear dielectric microscopy (SNDM) is described. For the purpose of obtaining fundamental knowledge on high-density ferroelectric data storage, several experiments on nanodomain formation in a lithium tantalate (LiTaO(3)) single crystal were conducted. As a result, a very small inverted domain with a radius of 6 nm was successfully formed in stoichiometric LiTaO(3) (SLT), and a domain dot array with an areal density of 1.5 Tbit/in.(2) was formed on congruent LiTaO(3) (CLT). Moreover, it was found that fast nanosecond domain switching could be achieved by reducing the thickness of a CLT plate sample. Additionally, the prototype high-density ferroelectric data storage system was developed. Using this system, writing data transfer rates were evaluated and 256 x 256 bit data were recorded with the areal densities of 258 and 717 Gbit/in(2).