Research Papers in Physics and Astronomy


Date of this Version



Published by EDP Sciences. Europhys. Lett., 58, 448 (2002). Copyright 2002. Permission to use.


CrO2 thin films, with crystallites of several microns size, provide the opportunity for the investigation of the intergrain tunneling between a few crystals separated by a 1-2 nm thick Cr2O3 film. A pronounced zero-bias anomaly of the conductance is found at low temperatures. Combined photoemission and inverse photoemission temperature-dependent studies confirm the occurrence of Coulomb blockade. For the strong-tunneling case (R2), the magnetoresistance decreases strongly with bias. For the weak-tunneling case (R>>RQ), the magnetoresistance decreases by a factor two with increasing bias, as predicted by a co-tunneling model.

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