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Detailed Program
Paper Number : EL-O05
Time Frame : 12:12~12:24
Presentation Date : Friday, 28, November
Session Name : Electronic Ceramics
Session Chair 1# : Jong-Sook Lee
Session Chair 2# : Nobuyasu Adachi
Effect of oxide electrode and synthesis conditions on electrical properties of CSD-derived Pb(Mg1/3Nb2/3)O3-PbTiO3 thin films
Takashi ARAI
Shizuoka University
Keywords: Thin Film, Chemical Solution Deposition, Synthesis condition, relaxor ferroelectrics

1. Introduction
Relaxor ferroelectrics Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN–PT) have attracted considerable attention because of their excellent electrical properties, such as high dielectricity and piezoelectricity. However, many previous papers have been reported the formation of the pyrochlore phase with lower electrical properties because of the similar formation energies of perovskite and pyrochlore phases. In addition, the reported electrical properties of PMN-PT thin films such as dielectric and piezoelectric properties are significantly lower than those of bulk ceramics and single crystals because processing parameters are still yet optimized for the thin films compared with the bulk ceramics and single crystals. In this study, LNO seeding layer was introduced and the effect of synthesis conditions on the electrical properties of the Chemical Solution Deposition (CSD)-derived PMN-PT thin films have been investigated to prepare single phase perovskite PMN-PT thin film with superior properties on a Si substrate at lower temperatures.
2. Experimental Procedure
PMN-PT and LNO thin films were prepared by CSD. The details of the LNO thin film deposition were described elsewhere. [1] The starting reagents for PMN–PT precursor solution were Pb(OCOCH3)2・3H2O, Ti(i-OC3H7)4, Mg(OC2H5)2, and Nb(OC2H5)5. Raw materials for A-site and B-site sources of perovskite structure were refluxed separately because Columbite method is effective to suppress the pyrochlore phase formation in bulk process. Then, they were mixed and refluxed. 2-aminoethanol was added to stabilize the obtained precursor solutions. In this process, excess amount of lead with 0 to 30 mol% were added to the precursor solutions. Although the lack of lead by the volatilization will cause the pyrochlore phase, too much addition of excess lead will result in the residual lead oxide or diffusion to the electrode. A concentration and composition of precursor solutions were 0.6M and MPB composition of 0.65PMN-0.35PT, respectively.
PMN–PT layers were deposited on LNO/Si substrate by spin coating. The as-deposited PMN–PT layer was dried at 150 ¡ÆC, preannealed at 350 or 450 ¡ÆC, and then annealed at 650 or 750 ¡ÆC to investigate the effect of synthesis conditions. Synthesis conditions will affect the microstructures, leading to the different electrical properties. Hence, the optimization of the heat treatment and the excess amount of lead are essential.
3. Results and Discussion
As a result, LNO seeding layer was effective to prepare the single phase (100)-oriented PMN-PT perovskite thin films and the annealing conditions significantly affected the electrical properties of the resultant PMN-PT thin films (Figure1). The optimized 0.65PMN-0.35PT thin film exhibited dielectric constant over 4000 (1 kHz, at room temperature) and relatively higher electrostrictive effect.
References:
[1] H. Suzuki, T. Naoe, H. Miyazaki, and T. Ota, J. Eur. Ceram. Soc. 27 (2007) 3769.
Acknowledgements :