Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 108: Spin-Dependent Transport Phenomena II (organized by MA)
TT 108.8: Vortrag
Donnerstag, 19. März 2015, 17:00–17:15, H 0112
Tunneling Anisotropic Magnetoresistance in oxide heterostructures — •Nico Homonnay1, Johannes Lotze1, Robert Göckeritz1, Alexander Müller1, Tim Richter1, and Georg Schmidt1,2 — 1Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle (Saale), Germany — 2Interdisziplinäres Zentrum für Materialwissenschaften, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle (Saale), Germany
We have investigated tunneling anisotropic magnetoresistance (TAMR) [1] in hybrid structures consisting of an epitaxial stack of a ferromagnetic oxide (La0.7Sr0.3MnO3, LSMO) and an oxide tunnel barrier (SrTiO3, STO) fitted with a non-magnetic metal contact. The oxide stack was deposited by pulsed laser deposition and metallization was done without breaking UHV conditions using various metals for different samples. The layers were processed to vertical tunneling devices with lateral dimensions of approx. 10 µm and the devices were investigated at low temperature in a 4He bath cryostate equipped with a 3D vector magnet. In all devices we observe TAMR which strongly depends on temperature, bias voltage and thickness of the tunnel barrier. The TAMR signal can be larger than 50 % which is more than 10 times bigger than reported for inorganic systems [1]. The magnetoresistance is clearly identified as TAMR by in-plane magnetic field sweeps at different angles. The TAMR signal persists up to a bias voltage of approx. 1 V and up to a temperature of 240 K which is well below the Curie temperature of the LSMO. [1] Gould et al., Phys. Rev. Lett. 93, 117203 (2004)