title: Finite curvature-mediated ferroelectricity.
abstract: We demonstrate that ferroelectric (FE) polarizations oriented along the finite thickness direction in ultrathin films are enhanced by the introduction of extreme curvature, thereby suppressing the finite-size-driven evolution of the FE phase transition temperature T(C). The measured responses within individual nanoshells possess magnitudes nearly three times that for their planar counterparts while exhibiting finite curvature-dependent offsets in FE switching hystereses. In stark contrast to the expected scaling of a depression of T(C) with inverse thickness, results based on modified Landau-Ginzburg model calculations indicate geometric curvature-driven polarization gradients in ultrathin films result in significant increases in T(C).
authors.affiliation: Department of Materials Science and Engineering, DrexelUniversity, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Stephen S
authors.initials: SS
authors.lastname: Nonnenmann
authors.forename: Oren D
authors.initials: OD
authors.lastname: Leaffer
authors.forename: Eric M
authors.initials: EM
authors.lastname: Gallo
authors.forename: Michael T
authors.initials: MT
authors.lastname: Coster
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Spanier