Influence of substrates on the crystal structure of pulsed laser deposited Pb(Mg_1/3Nb_2/3)O₃-29% PbTiO₃ thin films

Lead magnesium niobate-lead titanate [Pb(Mg_1/3Nb_2/3)O₃ (PMN)-PbTiO₃ (PT)] films were synthesized using pulsed laser deposition, and the effect of substrates on the deposition behavior of the PMN-PT film was investigated. Phase evolution of PMN-PT thin films was found to depend significantly on the type of the substrate used during deposition. Through a mixture of pyrochlore and perovskite was observed when films were deposited on a Pt/TiO₂/SiO₂/Si substrate, the oxide substrates, such as (Ba_0.5Sr_0.5)RuO₃/Si, SrTiO₃, a nd LaAlO₃, enabled the deposition of pure perovskite. Scanning Auger microprobe, transmission electron microscope, and x-ray diffraction analysis showed that an interfacial layer between the substrates and the oxide film was central to the phase evolution behavior. On the Pt/TiO₂/SiO₂/Si substrate, an interfacial layer of lead-platinum (Pb-Pt) played a major role in the formation of the pyrochlore phase. However, on oxide substrates, there was no interfacial layer and interdiffusion of A-site cations was observed between the PMN film and the oxide electrodes.