text: The main technological driver for the exploration of multiferroics has been their potential for controlling magnetism using electric fields via their magneto electric coupling. Such a capability could be technologically transformative, since the production of electric fields is far less energy intensive than the production of magnetic fields (which in turn require electric currents) that are used in most existing magnetism-based technologies. There have been successes in controlling the orientation of magnetism using an electric field, for example in heterostructures of conventional ferromagnetic metals and multiferroic BiFeO, as well as in controlling the magnetic state, for example from antiferromagnetic to ferromagnetic in FeRh.
  In multiferroic thin films, the coupled magnetic and ferroelectric order parameters can be exploited for developing magnetoelectronic devices. These include novel spintronic devices such as tunnel magnetoresistance (TMR) sensors and spin valves with electric field tunable functions. A typical TMR device consists of two layers of ferromagnetic materials separated by a thin tunnel barrier (~2 nm) made of a multiferroic thin film. In such a device, spin transport across the barrier can be electrically tuned. In another configuration, a multiferroic layer can be used as the exchange bias pinning layer. If the antiferromagnetic spin orientations in the multiferroic pinning layer can be electrically tuned, then magnetoresistance of the device can be controlled by the applied electric field. One can also explore multiple state memory elements, where data are stored both in the electric and the magnetic polarizations.