title: Control of ferroelectricity and magnetism in multi-ferroic BiFeO3 by epitaxial strain.
abstract: Recently, strain engineering has been shown to be a powerful and flexible means of tailoring the properties of ABO3 perovskite thin films. The effect of epitaxial strain on the structure of the perovskite unit cell can induce a host of interesting effects, these arising from either polar cation shifts or rotation of the oxygen octahedra, or both. In the multi-ferroic perovskite bismuth ferrite (BiFeO3-BFO), both degrees of freedom exist, and thus a complex behaviour may be expected as one plays with epitaxial strain. In this paper, we review our results on the role of strain on the ferroic transition temperatures and ferroic order parameters. We find that, while the Néel temperature is almost unchanged by strain, the ferroelectric Curie temperature strongly decreases as strain increases in both the tensile and compressive ranges. Also unexpected is the very weak influence of strain on the ferroelectric polarization value. Using effective Hamiltonian calculations, we show that these peculiar behaviours arise from the competition between antiferrodistortive and polar instabilities. Finally, we present results on the magnetic order: while the cycloidal spin modulation present in the bulk survives in weakly strained films, it is destroyed at large strain and replaced by pseudo-collinear antiferromagnetic ordering. We discuss the origin of this effect and give perspectives for devices based on strain-engineered BiFeO3.
authors.affiliation: Unité Mixte de Physique CNRS-Thales, , 1 Av. A. Fresnel, 91767 Palaiseau, and Université Paris-Sud, 91405 Orsay, France.
authors.forename: D
authors.initials: D
authors.lastname: Sando
authors.forename: A
authors.initials: A
authors.lastname: Agbelele
authors.forename: C
authors.initials: C
authors.lastname: Daumont
authors.forename: D
authors.initials: D
authors.lastname: Rahmedov
authors.forename: W
authors.initials: W
authors.lastname: Ren
authors.forename: I C
authors.initials: IC
authors.lastname: Infante
authors.forename: S
authors.initials: S
authors.lastname: Lisenkov
authors.forename: S
authors.initials: S
authors.lastname: Prosandeev
authors.forename: S
authors.initials: S
authors.lastname: Fusil
authors.forename: E
authors.initials: E
authors.lastname: Jacquet
authors.forename: C
authors.initials: C
authors.lastname: Carrétéro
authors.forename: S
authors.initials: S
authors.lastname: Petit
authors.forename: M
authors.initials: M
authors.lastname: Cazayous
authors.forename: J
authors.initials: J
authors.lastname: Juraszek
authors.forename: J-M
authors.initials: JM
authors.lastname: Le Breton
authors.forename: L
authors.initials: L
authors.lastname: Bellaiche
authors.forename: B
authors.initials: B
authors.lastname: Dkhil
authors.forename: A
authors.initials: A
authors.lastname: Barthélémy
authors.forename: M
authors.initials: M
authors.lastname: Bibes
keywords: BiFeO; Mössbauer spectroscopy; multi-ferroics; strain engineering