title: Superlattice induced by electron-beam irradiation in magnetic ferroelectric BiMnO(3).
abstract: Single-phased polycrystalline BiMnO(3) (hereinafter abbreviated as BMO) ceramic was fabricated via high-pressure solid-state reaction. Microstructure modification of selective grains, signalled by emergence of superlattice diffraction, was scrutinized by means of electron diffraction (ED) combined with high-resolution transmission electron microscopy (HRTEM). It was clearly evidenced that the well established C 2 monoclinic substructure (a = 9.53 Å, b = 5.61 Å, c = 9.85 Å and β = 110.67°) of BMO (Atou et al 1999 J. Solid State Chem. 145 639) is metastable and prone to be transformed to a new pseudocubic superstructure (a≈b≈c≈15.8 Å and α≈β≈γ≈90°) (Yang et al 2006 Phys. Rev. B 73 024114) when irradiated continuously by an electron beam. Magnetization measurement unveiled a unique ferromagnetic phase transition at 103 K, which corroborated our speculation that as-prepared BMO ceramic is free of polymorphism at ambient conditions.
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, PO Box 603, Beijing 100080, People's Republic of China.
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Chi
authors.forename: Hua
authors.initials: H
authors.lastname: Yang
authors.forename: Fengying
authors.initials: F
authors.lastname: Li
authors.forename: Richeng
authors.initials: R
authors.lastname: Yu
authors.forename: Changqing
authors.initials: C
authors.lastname: Jin
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Wang
authors.forename: Xiangyun
authors.initials: X
authors.lastname: Deng
authors.forename: Longtu
authors.initials: L
authors.lastname: Li