Ferroelectricity in Highly Ordered Arrays of Ultra-Thin-Walled Pb(Zr,Ti)O3Nanotubes Composed of Nanometer-Sized Perovskite Crystallites. - Jongok Kim; Sun A Yang; Yong Chan Choi; Jin Kyu Han; Keum Ok Jeong; Yong Ju Yun; Dong Jik Kim; Sang Mo Yang; Doohee Yoon; Hyeonsik Cheong; Ki-Seog Chang; Tae Won Noh; et al. (Nano Letters, 2008)