title: Electric field control of magnetic properties and electron transport in BaTiO₃-based multiferroic heterostructures.
abstract: In this paper, we report on a purely electric mechanism for achieving the electric control of the interfacial spin polarization and magnetoresistance in multiferroic tunneling junctions. We investigate micrometric devices based on the Co/Fe/BaTiO3/La0.7Sr0.3MnO3 heterostructure, where Co/Fe and La0.7Sr0.3MnO3 are the magnetic electrodes and BaTiO3 acts both as a ferroelectric element and tunneling barrier. We show that, at 20 K, devices with a 2 nm thick BaTiO3 barrier present both tunneling electroresistance (TER = 12   ±   0.1%) and tunneling magnetoresistance (TMR). The latter depends on the direction of the BaTiO3 polarization, displaying a sizable change of the TMR from  -0.32   ±   0.05% for the polarization pointing towards Fe, to  -0.12   ±   0.05% for the opposite direction. This is consistent with the on-off switching of the Fe magnetization at the Fe/BaTiO3 interface, driven by the BaTiO3 polarization, we have previously demonstrated in x-ray magnetic circular dichroism experiments.
authors.affiliation: Dipartimento di Fisica, Politecnico di Milano, Via G. Colombo 81, 20133 Milano, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Asa
authors.forename: L
authors.initials: L
authors.lastname: Baldrati
authors.forename: C
authors.initials: C
authors.lastname: Rinaldi
authors.forename: S
authors.initials: S
authors.lastname: Bertoli
authors.forename: G
authors.initials: G
authors.lastname: Radaelli
authors.forename: M
authors.initials: M
authors.lastname: Cantoni
authors.forename: R
authors.initials: R
authors.lastname: Bertacco