Tunneling magnetoresistance observed in La0.67Sr0.33MnO3/organic molecule/Co junctions

Tunneling magnetoresistance has been observed in organic based spintronic devices using the organic semiconductors tetraphenyl porphyrin (TPP) and aluminum tris(8-hyroxyquinoline) (Alq(3)) as the spacer layer between La0.67Sr0.33MnO3 (LSMO) and Co films. The evidence for tunneling is twofold: (1) nonlinear current and conductance versus voltage curves and (2) an increasing junction resistance with decreasing temperature. In general, the magnetoresistance is found to decrease with increasing bias voltage and increasing temperature in both Alq(3) and TPP junctions. These results demonstrate that organic molecules can form tunnel barriers that perform as well as most inorganic barrier materials on LSMO. (c) 2007 American Institute of Physics.