Novel room temperature multiferroics for random access memory elements

We have fabricated a variety of PZT-PFW (P bZr?.??Ti?.??O?)1-x(PbFe?/?W?/?O?)x [PZTFWx; 0.2 < x <0.4] single-phase tetragonal ferroelectrics via chemical solution deposition [polycrystalline] and pulsed laser deposition [epitaxial] onto Pt/Ti/SiO2/Si(100) and SrTiO?/Si substrates. These exhibit ferroelectricity and (weak) ferromagnetism above room temperature with strain coupling via electrostriction and magnetostriction. Application of modest magnetic field strength (μ?H < 1.0 T) destabilizes the long-range ferroelectric ordering and switches the polarization from approximately 22 μC/cm2 (0.22 C/m2) to zero (relaxor state). This offers the possibility of three-state logic (+P, 0, -P) and magnetically switched polarizations. Because the switching is of large magnitude (unlike the very small nanocoulomb per centimeter squared values in terbium manganites) and at room-temperature, commercial devices should be possible.