Tunneling conductance and interlayer exchange coupling of metallic magnetic trilayers decorated with additional ultra-thin nonmetallic spacers
Institute of Molecular Physics, PAN - 60-179 Poznań, Poland
2 Institut für Physik II der Universität - 93040 Regensburg, Germany
Accepted: 13 October 1998
By a very accurate recursion method based on the Kubo formula we calculate tunneling conductances of systems consisting of a nonmagnetic metallic spacer (MS) sandwiched between two ferromagnets (F) with additional ultra-thin nonmetallic (NM) interface layers. These hybrid structures are attached to voltage contacts by semi-infinite ideal lead wires (LW). The problem is treated in a two-band tight-binding model with hybridization. Our main finding is that the low-resistivity spin electron channel depends on the energy barrier width of the nonmetallic layer, and that with an asymmetric placement of the NM interface layers one can get large positive or negative values of the giant magnetoresistance with current-perpendicular-to-plane.
PACS: 75.70.-i – Magnetic films and multilayers / 73.40.Gk – Tunneling / 73.40.Ns – Metal-nonmetal contacts
© EDP Sciences, 1998