Electrical characterization of PMN-28%PT(001) crystalsused as thin-film substrates

Ferroelectric and piezoelectric properties of (001) 0.72 PbMg 1 / 3 Nb 2 / 3 O 3 - 0.28 PbTiO 3 (PMN-28%PT) single crystals have been investigated from cryogenic temperatures to 475 K. PMN-28%PT is used as piezoelectric substrate, e.g., in multiferroic heterostructures. Electric field-induced phase transformations have been examined by electrical characterization including measurements of polarization loops, dielectric permitivitty, and the resistance change in La 0.7 Sr 0.3 MnO 3 films deposited on the (001) face. The relaxor ferroelectric transition behavior was studied by means of time-dependent current measurements. A phase diagram is set up. PMN-28%PT is found to be at the border of the appearance of the monoclinc phase ( M C ) bridging the rhombohedral-tetragonal ( R - T ) transformation at higher PbTiO 3 contents. Measurements of the lattice expansion reveal that a high piezoelectric effect persists down to low temperatures. Therefore, PMN-28%PT single crystals are found to be appropriate substrates for application of piezoelectric strain to thin films over a broad temperature range.