Crystal orientation dependency of ferroelectric property in rhombohedral Pb(Zr,Ti)O3 films

Ferroelectric properties were investigated for (100), (110), and (111)-single-oriented rhombohedral Pb(Zr0.65Ti0.35)O3 films. Saturation polarization, Psat, was changed by the simple tilting angle of the polar axis from the film surface normal. On the other hand, (100)- and -oriented films prepared on (100) Si substrates showed similar Psat values due to the coexistence of orientation. The coercive field, Ec, of rhombohedral Pb(Zr0.65Ti0.35)O3 films was lower than that of tetragonal Pb(Zr0.4Ti0.6)O3 films. (100)-oriented rhombohedral films with SrRuO3 electrodes did not show noticeable degradation in polarization up to 1010 switching cycles. These results show that (100)-oriented rhombohedral Pb(ZrxTi1−x)O3 film is available to realize the low voltage operated ferroelectric random access memory instead of the present tetragonal Pb(ZrxTi1−x)O3 films.