Charge-ordering transition in iron oxide Fe4O5 involving competing dimer and trimer formation.
Phase transitions that occur in materials, driven, for instance, by changes in temperature or pressure, can dramatically change the materials' properties. Discovering new types of transitions and understanding their mechanisms is important not only from a fundamental perspective, but also for practical applications. Here we investigate a recently discovered Fe4O5 that adopts an orthorhombic CaFe3O5-type crystal structure that features linear chains of Fe ions. On cooling below ∼150 K, Fe4O5 undergoes an unusual charge-ordering transition that involves competing dimeric and trimeric ordering within the chains of Fe ions. This transition is concurrent with a significant increase in electrical resistivity. Magnetic-susceptibility measurements and neutron diffraction establish the formation of a collinear antiferromagnetic order above room temperature and a spin canting at 85 K that gives rise to spontaneous magnetization. We discuss possible mechanisms of this transition and compare it with the trimeronic charge ordering observed in magnetite below the Verwey transition temperature.
Bayerisches Geoinstitut, Universität Bayreuth, Universitätsstrasse 30, D-95447, Bayreuth, Germany.
Sergey V
SV
Ovsyannikov
Bayerisches Geoinstitut, Universität Bayreuth, Universitätsstrasse 30, D-95447, Bayreuth, Germany.|Laboratory of Crystallography, Universität Bayreuth, Universitätsstrasse 30, D-95447, Bayreuth, Germany.
Maxim
0000-0003-0248-1728
M
Bykov
Bayerisches Geoinstitut, Universität Bayreuth, Universitätsstrasse 30, D-95447, Bayreuth, Germany.|Laboratory of Crystallography, Universität Bayreuth, Universitätsstrasse 30, D-95447, Bayreuth, Germany.
Elena
E
Bykova
Frank Laboratory of Neutron Physics, JINR, 141980 Dubna, Russia.
Denis P
DP
Kozlenko
National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia.|Experimental Physics VI, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, 86135 Augsburg, Germany.
Alexander A
AA
Tsirlin
Institute of Metal Physics, Russian Academy of Sciences, Urals Division, GSP-170, 18 S. Kovalevskaya Str., Yekaterinburg 620041, Russia.
Alexander E
AE
Karkin
Institute of Metal Physics, Russian Academy of Sciences, Urals Division, GSP-170, 18 S. Kovalevskaya Str., Yekaterinburg 620041, Russia.|Institute for Solid State Chemistry, Russian Academy of Sciences, Urals Division, 91 Pervomayskaya Str., Yekaterinburg 620990, Russia.
Vladimir V
VV
Shchennikov
Frank Laboratory of Neutron Physics, JINR, 141980 Dubna, Russia.
Sergey E
SE
Kichanov
Bayerisches Geoinstitut, Universität Bayreuth, Universitätsstrasse 30, D-95447, Bayreuth, Germany.|Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China.
Huiyang
H
Gou
Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.|Department of Chemistry, Moscow State University, Leninskie Gory 1-3, Moscow 119991, Russia.
Artem M
AM
Abakumov
Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
Ricardo
R
Egoavil
Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
Johan
J
Verbeeck
Bayerisches Geoinstitut, Universität Bayreuth, Universitätsstrasse 30, D-95447, Bayreuth, Germany.
Catherine
0000-0001-5680-9106
C
McCammon
Swiss-Norwegian Beamlines at the European Synchrotron Radiation Facility, 38000, Grenoble, France.
Vadim
V
Dyadkin
Swiss-Norwegian Beamlines at the European Synchrotron Radiation Facility, 38000, Grenoble, France.
Dmitry
D
Chernyshov
Laboratory of Crystallography, Universität Bayreuth, Universitätsstrasse 30, D-95447, Bayreuth, Germany.
Sander
0000-0001-9645-8240
S
van Smaalen
Bayerisches Geoinstitut, Universität Bayreuth, Universitätsstrasse 30, D-95447, Bayreuth, Germany.
Leonid S
LS
Dubrovinsky