Large magnetoresistance values are obtained on tunnel junctions epitaxially deposited by pulsed-laser deposition and consisting of ferromagnetic manganite La_(0.67)Sr_(0.33)MnO_3 electrodes separated by various tunnel barriers: SrTiO_3, PrBaCu_(2.8)Ga_(0.2)O_7 and CeO_2. The magnetoresistance can be decomposed into a low-field and a high-field contribution. The latter is attributed to the presence of canted interfacial mangantie phases, as confirmed by the temperature behaviour of the resistance. A low-field magnetoresistance ratio of 450
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