Enhancing the low field magnetoresistive response in perovskite manganites

We report significant improvement in the magnetoresistive (MR) response of perovskite manganites for 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 ferromagnets with various magnetic properties, this technique allows for enormous flexibility in ‘‘designing’’ a desired MR response for the manganites, particularly in low fields.