title: Voltage-dependent magnetic phase transition in magneto-electric epitaxial Cr2O3 nanoclusters.
abstract: We observe, as a function of temperature, a second order magnetic phase transition in nanometric Cr2O3 clusters that are epitaxially embedded in an insulating MgO matrix. They are investigated through their tunnel magneto-resistance signature, the MgO layer being used as a tunnel barrier. We infer the small magnetic dipoles carried by the Cr2O3 clusters and provide evidence of a magnetic phase transition at low temperature in those clusters: they evolve from an anti ferromagnetic state, with zero net moment close to 0 K, to a weak ferromagnetic state that saturates above about 10 K. The influence of magneto-electric effects on the weak ferromagnetic phase is also striking: the second order transition temperature turns out to be linearly dependent on the applied electric field.
authors.affiliation: IPCMS, 23 rue du Loess, BP 43, F-67034 Strasbourg Cedex 2, France.
authors.forename: David
authors.initials: D
authors.lastname: Halley
authors.forename: Nabil
authors.initials: N
authors.lastname: Najjari
authors.forename: Florian
authors.initials: F
authors.lastname: Godel
authors.forename: Mohamad
authors.initials: M
authors.lastname: Hamieh
authors.forename: Bernard
authors.initials: B
authors.lastname: Doudin
authors.forename: Yves
authors.initials: Y
authors.lastname: Henry