《Ferroelectric Phase Transition in individual single-crystalline batio3 nanowires》.pdf

NANO LETTERS Ferroelectric Phase Transition in 2006 Vol. 6, No. 4 Individual Single-Crystalline BaTiO3 735739 Nanowires Jonathan E. Spanier,†,§, Alexie M. Kolpak,†,⊥ Jeffrey J. Urban,§ Ilya Grinberg,⊥ Lian Ouyang,§ Wan Soo Yun,‡,§ Andrew M. Rappe,*,⊥ and Hongkun Park*,§ Department of Chemistry and Chemical Biology, Har ard Uniersity, Cambridge Massachusetts 02138, Department of Materials Science and Engineering, Drexel Uniersity, Philadelphia, Pennsylania 19104, and The Makineni Theoretical Laboratories, Department of Chemistry, Uni ersity of Pennsylania, Philadelphia, Pennsyl ania 19104-6323 Received December 24, 2005 ABSTRACT We report scanned probe characterizations of the ferroelectric phase transition in individual barium titanate (BaTiO ) nanowires. Variable- 3 temperature electrostatic force microscopy is used to manipulate, image, and evaluate the diameter-dependent stability of ferroelectric polarizations. These measurements show that the ferroelectric phase transition temperature (T ) is depressed as the nanowire diameter (d ) C