title: Order-disorder antiferroelectric phase transition in a hybrid inorganic-organic framework with the perovskite architecture.
abstract: [(CH3)2NH2]Zn(HCOO)3, 1, adopts a structure that is analogous to that of a traditional perovskite, ABX3, with A = [(CH3)2NH2], B = Zn, and X = HCOO. The hydrogen atoms of the dimethyl ammonium cation, which hydrogen bond to oxygen atoms of the formate framework, are disordered at room temperature. X-ray powder diffraction, dielectric constant, and specific heat data show that 1 undergoes an order-disorder phase transition on cooling below 156 K. We present evidence that this is a classical paraelectric to antiferroelectric phase transition that is driven by ordering of the hydrogen atoms. This sort of electrical ordering associated with order-disorder phase transition is unprecedented in hybrid frameworks and opens up an exciting new direction in rational synthetic strategies to create extended hybrid networks for applications in ferroic-related fields.
authors.affiliation: Department of Chemistry & Biochemistry, Florida State University, Tallahassee, Florida 32306, USA.
authors.forename: Prashant
authors.initials: P
authors.lastname: Jain
authors.forename: Naresh S
authors.initials: NS
authors.lastname: Dalal
authors.forename: Brian H
authors.initials: BH
authors.lastname: Toby
authors.forename: Harold W
authors.initials: HW
authors.lastname: Kroto
authors.forename: Anthony K
authors.initials: AK
authors.lastname: Cheetham