Observation of large low field magnetoresistance in ramp-edge tunneling unctions based on doped manganite ferromagnetic electrodes and A SrTiO_3 insulator

摘要

We report the fabication of ferromagnet-insulator-ferromagnet junction devices using a ramp-geometry based on (La_(0.7)Sr_(0.3)MnO_3 ferromagnetic electrodes and a SrTiO_3 insulator. The multilayer thin films were deposited using pulsed laser deposition and the devices wer patterned using photithography and ion milling. As expected from the spin-dependent tunneling, the unction mangetoresistance depends on the relative orientation of the magnetization in the electrodes. The maximum junction magnetoresistance (JMR) of 30