title: Influence of pinholes on MgO-tunnel junction barrier parameters obtained from current-voltage characteristics.
abstract: Magnetic tunnel junctions (MTJs) with thin barriers are already used as read sensors in recording media. However, the presence of pinholes across such few A thick barriers cannot be excluded and one needs to investigate their effect on the MTJ-transport properties. By applying large electrical currents we could change the electrical resistance of the studied MgO MTJs (due to pinhole-size variations), and study how pinholes influence the barrier parameters (thickness t and height phi) obtained by fitting current-voltage characteristics to Simmons' model. We found that, with decreasing resistance, the barrier thickness (height) decreases (increases). These results were well reproduced by a model of parallel-resistances, allowing us to estimate pinhole-free barrier parameters.
authors.affiliation: IN, IFIMUP Unit, Rua do Campo Alegre, 687, 4169-007, Porto, Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Ventura
authors.forename: J M
authors.initials: JM
authors.lastname: Teixeira
authors.forename: J P
authors.initials: JP
authors.lastname: Araujo
authors.forename: J B
authors.initials: JB
authors.lastname: Sousa
authors.forename: R
authors.initials: R
authors.lastname: Ferreira
authors.forename: P P
authors.initials: PP
authors.lastname: Freitas
authors.forename: J
authors.initials: J
authors.lastname: Langer
authors.forename: B
authors.initials: B
authors.lastname: Ocker
authors.forename: W
authors.initials: W
authors.lastname: Maass