  We have fabricated a variety of "PZT-PFW"
(PbZr0.52Ti0.48O3)1-x(PbFe2/3W1/3O3)x [PZTFWx; 0.2 < x < 0.4] single-phase
tetragonal ferroelectrics via chemical solution deposition (CSD)
[polycrystalline] and pulsed laser deposition (PLD) [epitaxial] onto
Pt/Ti/SiO2/Si(100) and SrTiO3/Si substrates. These exhibit ferroelectricity and
(weak) ferromagnetism above room temperature with strain coupling via
electrostriction and magnetostriction. Application of modest magnetic field
strength ((mu)0H < 1.0 Tesla) destabilizes the long-range ferroelectric
ordering and switches the polarization from ca. 22 (mu)C/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 nC/cm2 values in terbium manganites) and at
room-temperature, commercial devices should be possible.
