Complex Cation and Spin Orders in the High-Pressure Ferrite CoFe3O5

Ka H Hong; Elena Solana-Madruga; Mauro Coduri; J Paul Attfield

doi:10.1021/acs.inorgchem.8b02458

Complex Cation and Spin Orders in the High-Pressure Ferrite CoFe₃O₅

Inorg Chem. 2018 Nov 19;57(22):14347-14352. doi: 10.1021/acs.inorgchem.8b02458. Epub 2018 Nov 1.

Authors

Ka H Hong¹, Elena Solana-Madruga¹, Mauro Coduri², J Paul Attfield¹

Affiliations

¹ Centre for Science at Extreme Conditions and School of Chemistry , University of Edinburgh , West Mains Road , Edinburgh EH9 3FD , United Kingdom.
² European Synchrotron Radiation Facility , 71 avenue des Martyrs , Grenoble 38000 , France.

PMID: 30382704
DOI: 10.1021/acs.inorgchem.8b02458

Abstract

A ferrite in the Sr₂Tl₂O₅-type MFe₃O₅ family with M = Co has been synthesized at 12 GPa pressure. Neutron diffraction shows the sample to be Co deficient with composition Co_0.6Fe_3.4O₅. The Co/Fe cation distribution is found to be profoundly different from those of MFe₃O₅ analogs and lies between normal and inverse limits, as Co²⁺ substitutes across trigonal prismatic and one of the two octahedral sites. CoFe₃O₅ shows complex magnetic behavior with weak ferromagnetism below T_C1 ≈ 300 K and a second transition to ferrimagnetic order at T_C2 ≈100 K. Spin scattering of carriers leads a substantial increase in the hopping activation energy below T_C1, and a small negative magnetoresistance is observed at low temperatures.