title: Structural and electric evidence of ferrielectric state in Pb₂MnWO₆ double perovskite system.
abstract: In this paper we describe the new ferri-electric compound Pb2MnWO6 (PMW), a double perovskite that can be considered as a novel structural prototype showing complex nuclear structure and interesting electric properties. According to single-crystal synchrotron data, PMW crystallizes in the noncentrosymmetric polar group Pmc21, in which the two symmetry-independent lead atoms give rise to a ferrielectric arrangement. The accurate crystallographic characterization indicates the presence of a complex distortion of the perovskite lattice driven by the local instability induced by the 6s(2) lone pair of the lead atoms. These peculiar structural features are confirmed by the complete electrical characterization of the system. Dielectric and transport measurements indicate an insulating character of the sample, while pyroelectric measurements point out a ferrielectric state characterized by different contributions. The magnetic transition at 45 K is accompanied by a magnetostrictive effect indicating a probable spin-lattice coupling. The characterizations carried out on PMW, showing the evidence of a coexistence of antiferromagnetism and ferrielectricity at low temperature, could lead to the definition of a new class of multiferroic materials.
authors.affiliation: Dipartimento di Chimica, Università di Parma , Parco Area delle Scienze 17/A, 43124 Parma, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Orlandi
authors.forename: Lara
authors.initials: L
authors.lastname: Righi
authors.forename: Riccardo
authors.initials: R
authors.lastname: Cabassi
authors.forename: Davide
authors.initials: D
authors.lastname: Delmonte
authors.forename: Chiara
authors.initials: C
authors.lastname: Pernechele
authors.forename: Fulvio
authors.initials: F
authors.lastname: Bolzoni
authors.forename: Francesco
authors.initials: F
authors.lastname: Mezzadri
authors.forename: Massimo
authors.initials: M
authors.lastname: Solzi
authors.forename: Marco
authors.initials: M
authors.lastname: Merlini
authors.forename: Gianluca
authors.initials: G
authors.lastname: Calestani