Ferroelectric molecular films for nanoscopic ultrahigh-density memories

The formation and visualization of nanometer-scale polarized domains in ultrathin ferroelectric molecular films by scanning-probe microscopy are described. These operations to the ferroelectric domains correspond to the "writing" and the "reading" process, respectively, for the data-storage application. In addition, nanometer-scale structures and the local electrical properties of the local domains, including the interface effect, are discussed. The achieved minimum diameter of the written ferroelectric domains was 30 nm. The size of the "recording" dot corresponds to the recording density of about 230 Gbit/in.(2). The "erasing" process by switching domains was also demonstrated. Furthermore, nanometer-scale ferroelectric domains using VDF oligomer molecular films were successfully formed, which has opened the way to the control of single molecular dipoles.