Novel approaches to field modulation of electronic and magnetic properties of oxides

The interplay of electronic charge and spin in many of the novel multicomponent oxides presents opportunities for new device concepts. In this paper we summarize three different approaches to making field-modulated devices. The first is the observation of a giant electroresistance (ER) effect in the colossal magnetoresistive manganites, where it is shown that in the same system two phenomena operate, colossal magnetoresistance (CMR) and colossal electroresistance (CER) and both processes are complementary. In the second example we show the modulation of the magnetic property of a diluted magnetic semiconductor by an electric field but the role of unidentified ferromagnetic entities cannot be ruled out at this stage. In the third and last case we show the example of the multiferroic materials where the magnetic properties are field dependent as well, but for totally different reasons.