Multiferroic materials are conventionally described as those possesing multiple ferroic order parameters. Routinely, this reffers to materials where the electric and magnetic responses are coupled. In such a material, applying an electric field can conrol the magnetic state, and vice versa.
While certain materials are intrinsically multiferroic, the coupling tends to be weak. Composite multiferroic materials are made by strain-coupling ferroelectric / piezoelectric materials with ferro / ferri / antiferromagnetic materials. Strain-mediated multiferroics provide an exceptionally energy efficient mechanism for controlling magnetism in micro/nanoscale devices. The Dynamic Active Materials Laboratory is interested in studying the funamental behavior of these materials, and exploiting their energy efficiency to develop novel multiferroic devices.
The videos to the left show how applying a voltage to a piezoelectric substrate controls the magnetization of adjacent magnetoelastic elements. The first video has nickel discs on a PZT substrate, while the second uses Terfenol-D. The color shows the applied electric potential, and the red arrows show the orientation of the local magnetic moment. The simulations in these videos couple the field of electrodynamcis with elasticity and micromagnetics to capture the system's dynamics.