title: Lead-Free α-La₂WO₆ Ferroelectric Thin Films.
abstract: (001)-Epitaxial La2WO6 (LWO) thin films are grown by pulsed laser deposition on (001)-oriented SrTiO3 (STO) substrates. The α-phase (high-temperature phase in bulk) is successfully stabilized with an orthorhombic structure (a = 16.585(1) Å, b = 5.717(2) Å, c = 8.865(5) Å). X-ray-diffraction pole-figure measurements suggest that crystallographic relationships between the film and substrate are [100]LWO ∥ [110]STO, [010]LWO ∥ [11̅0]STO and [001]LWO ∥ [001]STO. From optical properties, investigated by spectroscopic ellipsometry, we extract a refractive-index value around 2 (at 500 nm) along with the presence of two absorption bands situated, respectively at 3.07 and 6.32 eV. Ferroelectricity is evidenced as well on macroscale (standard polarization measurements) as on nanoscale, calling for experiments based on piezo-response force-microscopy, and confirmed with in situ scanning-and-tunneling measurements performed with a transmission electron microscope. This work highlights the ferroelectric behavior, at room temperature, in high-temperature LWO phase when stabilized in thin film and opens the way to new functional oxide thin films dedicated to advanced electronic devices.
authors.affiliation: Unité de Catalyse et de Chimie du Solide, UMR 8181 CNRS, Faculté des Sciences Jean Perrin, Université d'Artois , Rue Jean Souvraz, SP 18, F-62300 Lens, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Carlier
authors.affiliation: Unité de Catalyse et de Chimie du Solide, UMR 8181 CNRS, Faculté des Sciences Jean Perrin, Université d'Artois , Rue Jean Souvraz, SP 18, F-62300 Lens, France.
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Chambrier
authors.affiliation: Unité de Catalyse et de Chimie du Solide, UMR 8181 CNRS, Faculté des Sciences Jean Perrin, Université d'Artois , Rue Jean Souvraz, SP 18, F-62300 Lens, France.
authors.forename: Anthony
authors.initials: A
authors.lastname: Ferri
authors.affiliation: LENS, MIND-In2UB, Electronics Department, Universitat de Barcelona (UB) , Martí i Franquès 1, Barcelona 08028, Spain.
authors.forename: Sonia
authors.initials: S
authors.lastname: Estradé
authors.affiliation: Unité de Catalyse et de Chimie du Solide, UMR 8181 CNRS, Faculté des Sciences Jean Perrin, Université d'Artois , Rue Jean Souvraz, SP 18, F-62300 Lens, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Blach
authors.affiliation: LENS, MIND-In2UB, Electronics Department, Universitat de Barcelona (UB) , Martí i Franquès 1, Barcelona 08028, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Martín
authors.affiliation: Unité de Catalyse et de Chimie du Solide, UMR 8181 CNRS, Faculté des Sciences Jean Perrin, Université d'Artois , Rue Jean Souvraz, SP 18, F-62300 Lens, France.
authors.forename: Belkacem
authors.initials: B
authors.lastname: Meziane
authors.affiliation: LENS, MIND-In2UB, Electronics Department, Universitat de Barcelona (UB) , Martí i Franquès 1, Barcelona 08028, Spain.
authors.forename: Francesca
authors.initials: F
authors.lastname: Peiró
authors.affiliation: Unité de Catalyse et de Chimie du Solide, UMR 8181 CNRS, Ecole Nationale Supérieure Chimie Lille , Cité Scientifique, Bât C7, F-59652 Villeneuve d'Ascq, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Roussel
authors.affiliation: Institut d'Electronique, de Microélectronique et de Nanotechnologies, DOAE, UMR 8520 CNRS, Université de Valenciennes et du Hainaut-Cambrésis , F-59313 Valenciennes 9, France.
authors.forename: Freddy
authors.initials: F
authors.lastname: Ponchel
authors.affiliation: Institut d'Electronique, de Microélectronique et de Nanotechnologies, DOAE, UMR 8520 CNRS, Université de Valenciennes et du Hainaut-Cambrésis , F-59313 Valenciennes 9, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Rèmiens
authors.affiliation: LENS, MIND-In2UB, Electronics Department, Universitat de Barcelona (UB) , Martí i Franquès 1, Barcelona 08028, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Cornet
authors.affiliation: Unité de Catalyse et de Chimie du Solide, UMR 8181 CNRS, Faculté des Sciences Jean Perrin, Université d'Artois , Rue Jean Souvraz, SP 18, F-62300 Lens, France.
authors.forename: Rachel
authors.initials: R
authors.lastname: Desfeux
keywords: ferroelectricity; high-resolution X-ray diffraction; piezoresponse force microscopy; pulsed laser deposition; transmission electron microscopy