Structure and ferroelectric properties of high TcBi(Me)O3-PbTiO3 single crystal thin films

Pb(Zr,Ti)O
₃
(PZT) piezoelectric ceramics with higher Curie temperature T
_c
are necessary for a fabrication of better micro actuators, sensors, memories and/or piezoelectric micro electromechanical systems(MEMS). New piezoelectric materials with higher T
_c
beyond PZT are extensively studied. Among the new piezoelectric materials, Bi(Me)O
₃
-xPbTiO
₃
ceramics(Me: Yb, In, Sc) are fascinated for the higher T
_c
materials. In this paper thin films of single crystal (1-x)BiScO
₃
-xPbTiO
₃
(BS-xPT) were deposited by an rf-magnetron sputtering for a better understanding of ferroelectric performance of the BS-xPT. We have made a laminated composite structure comprising relaxed hetero-epitaxial single crystal thin films of high T
_c
BS-xPT (0.5≤x≤0.8) and SrRuO
₃
(SRO)/Pt/MgO hetero-structural substrates. It was confirmed their ferroelectric performances of the BS-xPT thin films were comparable to the PZT based thin films: a thin film transverse piezoelectricity e
_31,f
was -6.7C/m
²
at x=0.8 with 2P
_r
=~60μC/cm
²
, 2E
_c
=~250 kV/cm, and ε/ε
_o
=~150. The BS-0.8PT thin films exhibit extraordinary high T
_c
with T
_c
=750°C. The enhanced T
_c
is caused by the presence of the high temperature stable interface in the laminated composite structure. The present BS-xPT thin films have a high potential for a fabrication of high temperature stable piezoelectric MEMS beyond PZT.