title: Electric field-induced modification of magnetism in thin-film ferromagnets.
abstract: A large electric field at the surface of a ferromagnetic metal is expected to appreciably change its electron density. In particular, the metal's intrinsic magnetic properties, which are commonly regarded as fixed material constants, will be affected. This requires, however, that the surface has a strong influence on the material's properties, as is the case with ultrathin films. We demonstrated that the magnetocrystalline anisotropy of ordered iron-platinum (FePt) and iron-palladium (FePd) intermetallic compounds can be reversibly modified by an applied electric field when immersed in an electrolyte. A voltage change of -0.6 volts on 2-nanometer-thick films altered the coercivity by -4.5 and +1% in FePt and FePd, respectively. The modification of the magnetic parameters was attributed to a change in the number of unpaired d electrons in response to the applied electric field. Our device structure is general and should be applicable for characterization of other thin-film magnetic systems.
authors.affiliation: Institut Néel, CNRS/Université Joseph-Fourier [corrected], 25 Avenue des Martyrs, Boite Postale 166, F-38042 Grenoble Cedex 9, France. martin.weisheit@amd.com
authors.forename: Martin
authors.initials: M
authors.lastname: Weisheit
authors.forename: Sebastian
authors.initials: S
authors.lastname: Fähler
authors.forename: Alain
authors.initials: A
authors.lastname: Marty
authors.forename: Yves
authors.initials: Y
authors.lastname: Souche
authors.forename: Christiane
authors.initials: C
authors.lastname: Poinsignon
authors.forename: Dominique
authors.initials: D
authors.lastname: Givord