Phase stability and structural transitions in compositionally complex LnMO3 perovskites
Journal article, 2021
Entropy stabilised materials have possibilities for tailoring functionalities to overcome challenges in materials science. The concept of configurational entropy can also be applied to metal oxides, but it is unclear whether these could be considered as solid solutions in the case of perovskite-structured oxides and if the configurational entropy plays a stabilising role. In this study, compositionally complex perovskite oxides, LnMO3 (Ln = La, Nd, Sm, Ca and Sr, M = Ti, Cr, Mn, Fe, Co, Ni, and Cu), are investigated for their phase stability and magnetic behaviour. Phase-pure samples were synthesised, and the room temperature structures were found to crystallise in either Pnma or R3¯c space groups, depending on the composition and the resulting tolerance factor, while the structural transition temperatures correlate with the pseudo cubic unit cell volume. The techniques used included diffraction with X-rays and neutrons, both ex- and in-situ, X-ray photoelectron spectroscopy, magnetometry as well as electron microscopy. Neutron diffraction studies on one sample reveal that no oxygen vacancies are found in the structure and that the magnetic properties are ferrimagnetic-like with magnetic moments mainly coupled antiferromagnetically along the crystallographic c-direction. X-ray photoelectron spectroscopy gave indications of the oxidation states of the constituting ions where several mixed oxidation states are observed in these valence-compensated perovskites.
Magnetism
High entropy oxides
Phase transitions
Perovskites
Author
J. Cedervall
STFC Rutherford Appleton Laboratory
Stockholm University
Rebecca Clulow
Uppsala University
Hanna L.B. Boström
Uppsala University
Max Planck Society
Deep C. Joshi
Uppsala University
Mikael Andersson
Chalmers, Chemistry and Chemical Engineering, Energy and Material
Uppsala University
R. Mathieu
Uppsala University
Premysl Beran
Nuclear Physics Institute
European Spallation Source (ESS)
Ronald I. Smith
STFC Rutherford Appleton Laboratory
Jo Chi Tseng
Deutsches Elektronen-Synchrotron (DESY)
M. Sahlberg
Uppsala University
Pedro Berastegui
Uppsala University
Samrand Shafeie
Uppsala University
Chalmers, Physics, Materials and Surface Theory
Journal of Solid State Chemistry
0022-4596 (ISSN) 1095-726X (eISSN)
Vol. 300 122213Subject Categories
Inorganic Chemistry
Materials Chemistry
Condensed Matter Physics
DOI
10.1016/j.jssc.2021.122213