VOLTAGE-CONTROLLED COLOSSAL MAGNETORESISTANCE IN MANGANITE NORMAL-METAL HETEROSTRUCTURES/

It is well established that the resistivity of the manganites is a str ong function of the magnetization. Near the ferromagnetic ordering tem perature, colossal changes in the resistivity are seen in applied fiel ds of several Tesla; such fields are too large for a number of potenti al applications. An alternative approach is to change the state of mag netization by injecting spin polarized carriers into manganite/classic al ferromagnet heterostructures. In this work, results on manganite/no rmal-metal heterostructures in current perpendicular-to-plane geometry are reported. We observe a colossal magnetoresistance in fields of th e order of 1 T which we attribute to magnetic interface scattering. Th e magnitude of this magnetoresistive effect can be controlled by the a pplied voltage, i.e., the heterostructures act as magnetic sensors wit h variable sensitivity. Implications of the interface resistance on sp in injection from classical ferromagnets into manganites are discussed .