Dielectric and electromechanical properties of ferroelectric-relaxor 0.9 Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.1PbTiO_(3) thin films

摘要

Pyrochlore free 0.9Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.1PbTiO_(3) thin films were prepared from alkoxide-based solution precursors. Preferential (111) crystallographic orientation was obtained on TiO_(2)/Pt/TiO_(2)/SiO_(2)/Si substrates by spin coating. Dielectric, electrostrictive, and piezoelectric properties of the films were characterized in detail. Films show relaxor-like behavior, but with dielectric permittivity which is low (around 4300 at peak and at 340 Hz with E_(ac)=1.6×10~(6) V/m) compared to bulk ceramics and single crystals. Several parameters which might be responsible for this lower permittivity are suggested. The ac and dc field dependences of the dielectric response have been investigated. Electrostrictive coefficients, M_(11)(7.76×10~(-18) m~(2)/V~(2)) and Q_(11)(1.9×10~(-2) m~(4)C~(-2)), were determined by measuring strain and polarization as a function of the electric field (E_(ac)). The maximum field induced piezoelectric d_(33) coefficient is 100 pm/V and electrostrictive strains up to 1.2×10~(-3) (with an ac electric field of 140 kV/cm) were measured.