title: Multiferroic Phases and Transitions in Ferroelectric Lead Titanate Nanodots.
abstract: Discovery of novel phases and their associated transitions in low-dimensional nanoscale systems is of central interest as the origin of emergent phenomena and new device paradigms. Although typical ferroelectrics such as PbTiO3exhibit diverse phase transition sequences, the conventional incompatible mechanisms of ferroelectricity and magnetism keep them as simply nonmagnetic phases, despite the immense practical prospective of multiferroics in novel functional devices. Here, we demonstrate using density function theory that PbTiO3nanodots exhibit unconventional multiferroic phase transitions. The nanosize and nonstoichiometric effects intrinsic to nanodots bring about the coexistence of ferromagnetism with the host electric polarization, mediated by the termination and surface morphology. We also predict the key features of the size-dependent phase diagram of nanodots that involve a rich sequence of ferroelectric-multiferroic-ferromagnetic/nonmagnetic (FE-MF-FM/NM) multiferroic phase transitions. The present work thus provides an avenue to realizing multiferroics and multifunctional oxides in low-dimensional systems.
authors.affiliation: Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan.
authors.forename: Tao
authors.initials: T
authors.lastname: Xu
authors.affiliation: Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Shimada
authors.affiliation: Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Uratani
authors.affiliation: Institute of Systems Engineering, China Academy of Engineering Physics, Postbox 919-401, Mianyang 621900, China.
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kitamura