LARGE MAGNETORESISTANCE IN LA0.7SR0.3MNO3 SRTIO3/LA0.7SR0.3MNO3 RAMP-EDGE JUNCTIONS/

We report on the fabrication of ferromagnet-insulator-ferromagnet junc tion devices using a ramp-edge geometry based on (La0.7Sr0.3)MnO3 ferr omagnetic electrodes and a SrTiO3 insulator. The maximum junction magn etoresistance (JMR) as large as 23% is observed below 300 Oe at low te mperatures (T<100 K). Our ramp-edge junctions exhibit JMR of 6% at 200 K with a field less than 100 Oe. The device performance at room tempe rature is believed to be limited by both the nearly equivalent coerciv e fields in the electrodes and the magnetization process, rather than by the insulating barrier. (C) 1998 American Institute of Physics.