Abstract
We report significant improvement in the magnetoresistive (MR) response of perovskite manganites fur small applied fields by the use of heterostructures with soft ferromagnets. At room temperature, a 5900-fold enhancement of the MR response at 10 Oe in La2/3Ca1/3MnO3 has been achieved using (Mn,Zn)Fe2O4 as the soft ferromagnet. By utilizing soft ferromagnet with various magnetic properties, this technique allows for enormous flexibility in ''designing'' a desired MR response for the manganites, particularly in low fields. (C) 1996 American Institute of Physics.