Piezoelectric properties of polar-axis-oriented ferroelectric Bi4-xPrxTi3O12 thick films

The piezoelectric response of 1.2-mum-thick Bi4-xPrxTi3O12 (BPT, x = 0.3, 0.5, 0.7) ferroelectric films with polar-axis orientation is reported. Utilizing a long-range lattice-matching character, BPT films were grown by chemical solution deposition (CSD) on (101)-oriented IrO2 layers which were formed by the oxidation of Ir bottom layers during solution depositions. An effective piezoelectric coefficient d(33) = 36pm/V comparable to that of Bi4Ti3O12 (BIT) single crystal was measured in BPT thick films with x = 0.3. Related to the decrease in P-s, the total strain epsilon(total) decreased with increasing x. Stripe-shaped domain structures of similar to20 nm in width were observed in some grains in BPT thick films by piezoresponse force microscopy (PFM) and transmission electron microscopy (TEM). These structures could be attributed to 90degrees domain walls. The reconfiguration of these domains by the elecric field may occur to contribute to the ferroelectric polarizations resulting in a large value of P-sat = 50muC/cm(2) in BPT thick films with x = 0.3.