X‐ray Powder Diffraction Structural Phase‐Transition Study Of La(Cr1‐xMnx)O3 (x = 0 To 0.25) Using The Rietveld Method Of Analysis

Author

Scott A. Howard
Jen‐Kuan ‐K Yau
Harlan U. Anderson, Missouri University of Science and TechnologyFollow

Abstract

The La(Cr_1‐xMn_x)O₃ (x = 0 to 0.25) system exhibited a displacive phase transformation from an orthorhombic to a rhombohedral structure at temperatures ranging from about 256°C at x= 0 to 305°C at x= 0.25. The Rietveld method of X‐ray analysis was used to determine structural characteristics and to assay phase concentrations when multiple phases were present. Indications were that the Mn ions on the B site affected the transition temperature through an ionic size effect; i.e., Mn³⁺, with a larger ionic size than Cr³⁺, increased the transition temperature while the presence of the smaller Mn⁴⁺ ions reduced it. A hysteresis was also observed with respect to the phase transformation as a function of temperature. The phase transformation was associated with a change in the rotation of the oxygen octahedra from an antiphase to an in‐phase tilt sequence. Copyright © 1992, Wiley Blackwell. All rights reserved

Recommended Citation

S. A. Howard et al., "X‐ray Powder Diffraction Structural Phase‐Transition Study Of La(Cr1‐xMnx)O3 (x = 0 To 0.25) Using The Rietveld Method Of Analysis," Journal of the American Ceramic Society, vol. 75, no. 6, pp. 1685 - 1687, Wiley, Jan 1992.

The definitive version is available at https://doi.org/10.1111/j.1151-2916.1992.tb04247.x

Department(s)

Materials Science and Engineering

Publication Status

Full Access

Keywords and Phrases

chromium; lanthanum oxide; manganese; phase transformation; X‐ray diffraction

International Standard Serial Number (ISSN)

1551-2916; 0002-7820

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2023 Wiley, All rights reserved.

Publication Date

01 Jan 1992