Valence changes of manganese and structural phase transitions in Sr{sub 1−x}Pr{sub x}MnO₃ (0.1≤x≤0.6)

Journal Article · Wed May 01 00:00:00 EDT 2013 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2013.01.034· OSTI ID:22306275

Tan, Teck-Yee; Martin, Nicolas; Zhou, Qingdi ^[1]; Gu, Qinfen; Kimpton, Justin A. ^[2]; Zhang, Zhaoming ^[3]; Jang, Ling-Yun ^[4]

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1. School of Chemistry, The University of Sydney, New South Wales 2006 (Australia)
2. Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia)
3. Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2234 (Australia)
4. Facility Utilization Group, Experiment Facility Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China)

Fifteen perovskite manganites Sr{sub 1–x}Pr{sub x}MnO₃, x=0.1–0.6 in steps as fine as 0.025, have been synthesized by solid state methods and their crystal structures determined using synchrotron X-ray powder diffraction. At room temperature two first order phase transitions associated with changes in the orbital ordering and the tilting of the corner shared MnO₆ octahedra are evident cubic/Pm3⁻m→{sup x≈0.15}tetragonal/(I4/mcm)→{sup x≈0.45}orthorhombic/Imma, with two phase regions associated with both transitions. Heating the Pr rich oxide Sr₀.₅Pr₀.₅MnO₃ provides a rare example where chemical pressure and temperature result in a different sequence of transitions Imma–R3⁻c–Pm3⁻m, reflecting the importance of the Pr 4f electrons. X-ray absorption near-edge structure (XANES) measurements at the Mn K and Pr L₃ edges show the valence state of the Mn linearly decreases with increasing Pr content whereas the Pr remains +3 across the entire series. Magnetic susceptibility measurements for selected samples are presented. - Graphical abstract: The Mn oxidation state and the phase diagram of Sr{sub 1–x}Pr{sub x}MnO₃ (0.1<0.6) above ambient temperature has established using synchrotron X-ray diffraction data. Highlights: • Structures of Sr{sub 1–x}Pr{sub x}MnO₃, x=0.1–0.6, established using synchrotron XRD. • Two first order phase transitions due to orbital ordering and the tilting of MnO₆ octahedra observed. • High temperature phase transitions investigated. • Valence state of Mn and Pr determined using XANES.

• OSTI ID: 22306275
• Journal Information: Journal of Solid State Chemistry, Vol. 201; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION
ABSORPTION SPECTROSCOPY
AMBIENT TEMPERATURE
CUBIC LATTICES
HEATING
ION MICROPROBE ANALYSIS
MAGNETIC SUSCEPTIBILITY
MANGANESE
MANGANESE OXIDES
PEROVSKITE
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
SOLIDS
SYNCHROTRONS
TETRAGONAL LATTICES
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY