title: Four-state ferroelectric spin-valve.
abstract: Spin-valves had empowered the giant magnetoresistance (GMR) devices to have memory. The insertion of thin antiferromagnetic (AFM) films allowed two stable magnetic field-induced switchable resistance states persisting in remanence. In this letter, we show that, without the deliberate introduction of such an AFM layer, this functionality is transferred to multiferroic tunnel junctions (MFTJ) allowing us to create a four-state resistive memory device. We observed that the ferroelectric/ferromagnetic interface plays a crucial role in the stabilization of the exchange bias, which ultimately leads to four robust electro tunnel electro resistance (TER) and tunnel magneto resistance (TMR) states in the junction.
authors.affiliation: Max Planck Institute of Microstructure Physics, Halle, D-06120, Germany.
authors.forename: Andy
authors.initials: A
authors.lastname: Quindeau
authors.affiliation: 1] Max Planck Institute of Microstructure Physics, Halle, D-06120, Germany [2] Department of Physics, University of Warwick, Coventry, CV4 7AL, United Kingdom.
authors.forename: Ignasi
authors.initials: I
authors.lastname: Fina
authors.affiliation: 1] Institute of Physics ASCR, v.v.i., Cukrovarnická 10, Praha 6, 162 53, Czech Republic, [2] Centre d'Investigacions en Nanociencia i Nanotechnologia (ICN2), CSIC-ICN, Bellaterra, Barcelona, 08193, Spain.
authors.forename: Xavi
authors.initials: X
authors.lastname: Marti
authors.affiliation: Department of Physics, University of Warwick, Coventry, CV4 7AL, United Kingdom.
authors.forename: Geanina
authors.initials: G
authors.lastname: Apachitei
authors.affiliation: Diamond Light Source, Harwell Science and Innovation Campus, Chilton, Didcot OX11 0DE, United Kingdom.
authors.forename: Pilar
authors.initials: P
authors.lastname: Ferrer
authors.affiliation: Diamond Light Source, Harwell Science and Innovation Campus, Chilton, Didcot OX11 0DE, United Kingdom.
authors.forename: Chris
authors.initials: C
authors.lastname: Nicklin
authors.affiliation: Max Planck Institute of Microstructure Physics, Halle, D-06120, Germany.
authors.forename: Eckhard
authors.initials: E
authors.lastname: Pippel
authors.affiliation: Max Planck Institute of Microstructure Physics, Halle, D-06120, Germany.
authors.forename: Dietrich
authors.initials: D
authors.lastname: Hesse
authors.affiliation: 1] Max Planck Institute of Microstructure Physics, Halle, D-06120, Germany [2] Department of Physics, University of Warwick, Coventry, CV4 7AL, United Kingdom.
authors.forename: Marin
authors.initials: M
authors.lastname: Alexe