  We present a magnetoresistive-photoresistive device based on the interaction
of a piezomagnetic CoFe thin film with a photostrictive BiFeO3 substrate that
undergoes light-induced strain. The magnitude of the resistance and
magnetoresistance in the CoFe film can be controlled by the wavelength of the
incident light on the BiFeO3. Moreover, a light-induced decrease in anisotropic
magnetoresistance is detected due to an additional magnetoelastic contribution
to magnetic anisotropy of the CoFe film. This effect may find applications in
photo-sensing systems, wavelength detectors and can possibly open a research
development in light-controlled magnetic switching properties for next
generation magnetoresistive memory devices.
