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Title: Structural and electronic properties of Sr{sub 1−x}Ca{sub x}Ti{sub 0.5}Mn{sub 0.5}O{sub 3}

The series of Sr{sub 1−x}Ca{sub x}Ti{sub 1/2}Mn{sub 1/2}O{sub 3} perovskites has been prepared using solid state methods and their structures determined using combination of synchrotron X-ray and powder neutron diffraction. At room temperature the crystal structure evolves with increasing Ca content from Pm3{sup ¯}m→tetragonal I4/mcm→orthorhombic Pbnm, as a consequence of the sequential introduction of cooperative tilting of the (Ti/Mn)O{sub 6} octahedra. X-ray absorption measurements show the Mn is tetravalent in all oxides. Magnetic susceptibility measurements demonstrate all the oxides to be paramagnetic at room temperature, with a transition to a spin glass arrangement occurring at low temperatures. Electrical measurements prove that all the members are semiconductors and their activation energy increase with Ca doping amount. - Graphical abstract: Changes in the bond valence sums for the A- and B-sites in Sr{sub 1−x}Ca{sub x}Mn{sub 0.5}Ti{sub 0.5}O{sub 3} reflect changes in the symmetry of the oxides. - Highlights: • Structures of the Sr{sub 1−x}Ca{sub x}Ti{sub 1/2}Mn{sub 1/2}O{sub 3} perovskites studies using synchrotron X-ray and powder neutron diffraction. • Tilting of the octahedra occurs as Ca content increases. • Changes in the bond valence sums for the A- and B-sites cations reflect changes in the crystal symmetry. • Magnetic properties dependent of Camore » content.« less
Authors:
;  [1] ;  [1] ; ; ;  [2]
  1. School of Chemistry, The University of Sydney, Sydney, NSW 2006 (Australia)
  2. Institute of Materials Structure Science, High Energy Accelerator Research Organization KEK, Tsukuba, Ibaraki 305-0801 (Japan)
Publication Date:
OSTI Identifier:
22334234
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 213; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION; ACTIVATION ENERGY; CATIONS; CRYSTALS; CUBIC LATTICES; MAGNETIC SUSCEPTIBILITY; NEUTRON DIFFRACTION; ORTHORHOMBIC LATTICES; OXIDES; PARAMAGNETISM; PEROVSKITE; PHASE TRANSFORMATIONS; SEMICONDUCTOR MATERIALS; SOLIDS; SPIN GLASS STATE; X RADIATION