Physics Colloquium: Georg Schmidt, “Voltage Controlled Tunnel Barriers in Organic Spin Valves Based on Tunneling Anisotropic Magnetoresistance” (2014-03-27)

Calendar

When:

March 27, 2014 @ 7:30 pm – 8:30 pm

2014-03-27T19:30:00+00:00

2014-03-27T20:30:00+00:00

Where:

4138 Physics Research Building

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Abstract

We demonstrate that in an organic spin valve with a La0.7Sr0.3MnO3 (LSMO) electrode and a non-magnetic counter electrode voltage pulses can change the resistance by almost two orders of magnitude. Additionally tunneling anisotropic magnetoresistance (TAMR) up to 17% can be observed. Our experiments show that the width and height of the injection barrier between the LSMO and the organic semiconductor are changed by applied voltage pulses. Our observations can be explained by the creation of oxygen vacancies in the LSMO whose spatial distribution can be modified by electric fields. Large reverse voltages can reset the device to its original state.