Ferromagnetism induced by entangled charge and orbital orderings in ferroelectric titanate perovskites

Bristowe, N. C. and Varignon, J. and Fontaine, D. and Bousquet, E. and Ghosez, Ph. (2015) Ferromagnetism induced by entangled charge and orbital orderings in ferroelectric titanate perovskites. Nature Communications, 6 . ISSN 2041-1723. E-ISSN 2041-1723. (doi:https://doi.org/10.1038/ncomms7677) (Full text available)

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Abstract

In magnetic materials, the Pauli exclusion principle typically drives anti-alignment between electron spins on neighbouring species resulting in antiferromagnetic behaviour. Ferromagnetism exhibiting spontaneous spin alignment is a fairly rare behaviour, but once materialized is often associated with itinerant electrons in metals. Here we predict and rationalize robust ferromagnetism in an insulating oxide perovskite structure based on the popular titanate series. In half-doped layered titanates, the combination of Jahn-Teller and oxygen breathing motions opens a band gap and creates an unusual charge and orbital ordering of the Ti d electrons. It is argued that this intriguingly intricate electronic network favours the elusive inter-site ferromagnetic (FM) ordering, on the basis of intra-site Hund's rules. Finally, we find that the layered oxides are also ferroelectric with a spontaneous polarization approaching that of BaTiO3. The concepts are general and design principles of the technologically desirable FM ferroelectric multiferroics are presented.

Item Type: Article
Subjects: Q Science > QC Physics > QC173.45 Condensed Matter
Q Science > QC Physics > QC176 Solid state physics
Q Science > QD Chemistry > QD478 Solid State Chemistry
Q Science > QC Physics > QC176.8.N35 Nanoscience, nanotechnology
Q Science > QD Chemistry > QD473 Physical properties in relation to structure
Divisions: Faculties > Sciences > School of Physical Sciences
Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Nicholas Bristowe
Date Deposited: 21 Feb 2017 16:01 UTC
Last Modified: 22 Feb 2017 16:14 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/60254 (The current URI for this page, for reference purposes)
Bristowe, N. C.: https://orcid.org/0000-0003-1286-8440
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