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Ferroelectrics Characterization and Modeling Part 8

Tham khảo tài liệu 'ferroelectrics characterization and modeling part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Changes of Crystal structureand Electrical Properties withFilm Thickness and_ Zr Zr Ti RatiO for Epitaxial Pb Zr Ti O3 films Grown on 100 cSrRuO3 100 SrTiO3 Substrates. 235 50nm 250nm 50nm 250nm 50nm 250nm 50nm 250nm 20 30 40 50 20 CuKa deg Fig. 6. XRD ffl-20 diagrams of PZT films having 50 and 250 nm in thickness and different Zr Zr Ti ratio from small Zr Zr Ti ratio a to large Zr Zr Ti ratio d . 236 Ferroelectrics - Characterization and Modeling 62 Thickness 50nm 0.415 0.410 0.405 0.400 0.395 0.390 68 66 64 1.07 1.06 1.05 1.04 1.03 1.02 1.01 1.00 70 1 1 _ 1 1 1 1 1 1 1 Shirane et al t - a - Illi 1 1 1 1 1 - X - - - 1 1 1 1 1 1 1 1 1 - -i. b Illi 1 1 1 1 1 _ - _ ỈI yr 1 1 1 1 1 1 1 1 1 c - 1 1 1 0.0 0.4 0.3 0.2 0.1 0.0 0.2 0.4 0.6 0.8 1.0 Zr Zr Ti ratio m 0.415 0.410 0.405 0.400 0.395 0.390 68 66 64 Thickness 250n 1.07 1.06 1.05 1.04 1.03 1.02 1.01 1.00 70 1 1 1 1 1 1 H e 1 1 zx Shirane et al . d - 1 1 1 1 ị 1 1 1 1 1 1 1 1 . e - 1 1 1 1 1 1 1 1_ 1 1 1 _ . . f - 1 1 0.0 0.4 0.3 0.2 0.1 8 Ị 62 0.0 0.2 0.4 0.6 0.8 1.0 Zr Zr Ti ratio 8 Ị Ẹ Ẹ c I 5 Fig. 7. Lattice parameters a d tetragonality c a ratio and the internal angles and b e and unit cell volume c f as a function of Zr Zr Ti ratio for a - c 50 and d - f 250 nm thick films. Dashed lines are powder data reported by Shirane et al Shirane Suzuki 1952 . The c-domain relative volume fractions Vc are shown in Fig. 8 as a function of the Zr Zr Ti ratio. These values are obtained from HRXRD-RSM characterization reported elsewhere Morioka et al. 2004a . On this figure we notice that the 50 nm thick Films are fully polar axis-oriented films 001 orientation regardless of the Zr Zr Ti ratio up to 54 Fig. 8 a . On the other hand Vc decreased with increasing PZT film thickness. Indeed we notice for the 250 nm thick films Fig. 8 b that Vc is about 70 up to Zr Zr Ti 0.45. In the intermediate region Vc fluctuates between 55 and 75 due to the experimental errors induced by the tetragonal and rhombohedral duplicated peaks Saito