CURRENT SWITCHING OF RESISTIVE STATES IN MAGNETORESISTIVE MANGANITES

Magnetoresistive devices (based on, for example, magnetic multilayers( 1)) exhibit large changes in electrical resistance in response to a ma gnetic field, which has led to dramatic improvements in the data densi ty and reading speed of magnetic recording systems. Manganese oxides h aving a perovskite structure (the so-called manganites) can exhibit a magnetoresistive response that is many orders of magnitude larger than that found for other materials, and there is therefore hope that thes e compounds might similarly be exploited for recording applications(2- 11). Here we show that the switching of resistive states in the mangan ites can be achieved not only by a magnetic field, but also by an elec tric field. For manganites of the form Pr1-xCaxMnO3, we iind that an e lectrical current (and by implication a static electric held) triggers the collapse of the low-temperature, electrically insulating charge-o rdered state to a metallic ferromagnetic state. We suggest that such a phenomenon could be exploited to pattern conducting ferromagnetic dom ains within an insulating antiferromagnetic matrix, and so provide a r oute for fabricating micrometre- or nanometre-scale electromagnets.