Structure and magnetism of the Rh4+-containing perovskite oxides La0.5Sr0.5Mn0.5Rh0.5O3 and La0.5Sr0.5Fe0.5Rh0.5O3

Nijat Hasanli; Alex Scrimshire; Paul A Bingham; Robert G Palgrave; Michael A Hayward

doi:10.1039/d0dt02466j

Structure and magnetism of the Rh⁴⁺-containing perovskite oxides La_0.5Sr_0.5Mn_0.5Rh_0.5O₃ and La_0.5Sr_0.5Fe_0.5Rh_0.5O₃

Dalton Trans. 2020 Aug 18;49(32):11346-11353. doi: 10.1039/d0dt02466j.

Authors

Nijat Hasanli¹, Alex Scrimshire², Paul A Bingham², Robert G Palgrave³, Michael A Hayward¹

Affiliations

¹ Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK. michael.hayward@chem.ox.ac.uk.
² Materials and Engineering Research Institute, Sheffield Hallam University, City Campus, Howard Street, Sheffield, S1 1WB, UK.
³ Department of Chemistry, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK.

PMID: 32766623
DOI: 10.1039/d0dt02466j

Abstract

Synchrotron X-ray powder diffraction data indicate that La0.5Sr0.5Mn0.5Rh0.5O3 and La0.5Sr0.5Fe0.5Rh0.5O3 adopt distorted perovskite structures (space group Pnma) with A-site and B-site cation disorder. A combination of XPS and 57Fe Mössbauer data indicate the transition metal cations in the two phases adopt Mn3+/Rh4+ and Fe3+/Rh4+ oxidation state combinations respectively. Transport data indicate both phases are insulating, with ρ vs. T dependences consistent with 3D variable-range hopping. Magnetisation data reveal that La0.5Sr0.5Mn0.5Rh0.5O3 adopts a ferromagnetic state below Tc ∼ 60 K, which is rationalized on the basis of coupling via a dynamic Jahn-Teller distortion mechanism. In contrast, magnetic data reveal La0.5Sr0.5Fe0.5Rh0.5O3 undergoes a transition to a spin-glass state at T ∼ 45 K, attributed to frustration between nearest-neighbour Fe-Rh and next-nearest-neighbour Fe-Fe couplings.