title: SrMnO3 Thermochromic Behavior Governed by Size-Dependent Structural Distortions.
abstract: The influence of particle size in both the structure and thermochromic behavior of 4H-SrMnO3 related perovskite is described. Microsized SrMnO3 suffers a structural transition from hexagonal (P63/mmc) to orthorhombic (C2221) symmetry at temperature close to 340 K. The orthorhombic distortion is due to the tilting of the corner-sharing Mn2O9 units building the 4H structural type. When temperature decreases, the distortion becomes sharper reaching its maximal degree at ∼125 K. These structural changes promote the modification of the electronic structure of orthorhombic SrMnO3 phase originating the observed color change. nano-SrMnO3 adopts the ideal 4H hexagonal structure at room temperature, the orthorhombic distortion being only detected at temperature below 170 K. A decrease in the orthorhombic distortion degree, compared to that observed in the microsample, may be the reason why a color change is not observed at low temperature (77 K).
authors.affiliation: Departamento de Química Inorgánica, Facultad de CC. Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain.
authors.forename: Irma N
authors.initials: IN
authors.lastname: González-Jiménez
authors.affiliation: Instituto de Ciencia de Materiales, CSIC , Cantoblanco, 28049 Madrid, Spain.
authors.forename: Esteban
authors.initials: E
authors.lastname: Climent
authors.affiliation: Departamento de Química Inorgánica, Facultad de CC. Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain.
authors.forename: Almudena
authors.initials: A
authors.lastname: Torres-Pardo
authors.affiliation: Departamento de Química Inorgánica, Facultad de CC. Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Hernando
authors.affiliation: Departamento de Química Inorgánica, Facultad de CC. Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain.
authors.forename: Ana E
authors.initials: AE
authors.lastname: Sánchez-Peláez
authors.affiliation: E.U.I.T. Industrial, Universidad Politécnica de Madrid , Ronda de Valencia 3, 28012 Madrid, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Fernández-Martínez
authors.affiliation: ILL , 71 avenue des Martyrs CS 20156, 38042 Grenoble Cedex 9, France.
authors.forename: M Teresa Fernández
authors.initials: MT
authors.lastname: Díaz
authors.affiliation: Departamento de Química Inorgánica, Facultad de CC. Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain.|Centro Nacional de Microscopía Electrónica , 28040 Madrid, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: González-Calbet
authors.affiliation: Instituto de Ciencia de Materiales, CSIC , Cantoblanco, 28049 Madrid, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: de Andrés
authors.affiliation: Departamento de Química Inorgánica, Facultad de CC. Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain.
authors.forename: Áurea
authors.initials: Á
authors.lastname: Varela
authors.affiliation: Departamento de Química Inorgánica, Facultad de CC. Químicas, Universidad Complutense de Madrid , 28040 Madrid, Spain.
authors.forename: Marina
authors.initials: M
authors.lastname: Parras