Structural and electrical characterization of heteroepitaxial Pb[Yb_1/2Nb_1/2]O₃-PbTiO₃ thin films

The pulsed laser deposition process has been used to prepare heteroepitaxial (1-x) Pb[Yb_1/2Nb_1/2]O₃-xPbTiO₃(PYbN-PT, x= 0.4,0.5) thin films on single crystalline (001)_pcSrppSrRuO₃/LaAlO₃ and (111)_pcSrRuO3/SrTiO₃ substrates (the subscript pc refers here to the pseudocubic subcell). High laser frequencies (f- 16 Hz) and 300 mTorr of background O₃/O₃ in the chamber during deposition provide stoichiometric and high crystalline quality heterostructures. Temperatures in the 560-660 °C range lead to improved microstructures as well as good dielectric and ferroelectric properties consistent with those of PYbN-PT ceramics. In particular, films show room temperature dielectric constants greater than 1300 and exhibit well-developed hysteresis loops with remanent polarizations (P_r) as high as 40-50 μCcm^-2. Results are discussed in terms of film composition and crystallinity.