Ferroelectricity in Highly Ordered Arrays of Ultra-Thin-Walled Pb(Zr,Ti)O sub(3) Nanotubes Composed of Nanometer-Sized Perovskite Crystallites

We report the first unambiguous ferroelectric properties of ultra-thin- walled Pb(Zr,Ti)O sub(3) (PZT) nanotube arrays, each with 5 nm thick walls and outer diameters of 50 nm. Ferroelectric switching behavior with well- saturated hysteresis loops is observed in these ferroelectric PZT nanotubes with P sub(r) and E sub(c) values of about 1.5 mu C cm super(-2) and 86 kV cm super(-1), respectively, for a maximum applied electric field of 400 kV cm super(- 1). These PZT nanotube arrays (10 super(12) nanotubes cm super(-2)) might provide a competitive approach toward the development of three-dimensional capacitors for the terabyte ferroelectric random access memory.