Crystallographic characterization of epitaxial Pb(Zr,Ti)O3 films with different Zr/Ti ratio grown by radio-frequency-magnetron sputtering

Abstract

Crystallographic structure of as-grown epitaxial Pb͑Zr,Ti͒O 3 ͑PZT͒ films was investigated with regard to the Zr/Ti ratio and crystalline orientation. PZT films with ͑001͒ and ͑111͒ orientation were epitaxially grown on ͑100͒ and ͑111͒SrTiO 3 substrates respectively using radio-frequency ͑rf͒ sputtering. Four circle x-ray diffraction measurements revealed that the crystallographic dependence on Zr/Ti composition in PZT films was much different from bulk PZT. In particular, ͑001͒-oriented PZT films showed tetragonal structure even in the Zr/Ti composition of 70/30 where the bulk PZT ceramics are rhombohedral phase. In addition, although ͑001͒-oriented PZT films with Zr/Ti ratio of 53/47 and 70/30 showed tetragonal structure, ͑111͒-oriented PZT films with the same Zr/Ti ratio were identified as the rhombohedral structure. The cell volume of the PZT films with both orientations increased, suggesting the excess Pb atoms in the films due to the impinging energetic sputtered particles induces the anomalous crystalline structure of the PZT films. Dielectric properties of the PZT films exhibited stable value independent of Zr/Ti ratio and characteristic increase of dielectric constant near Zr/Tiϭ53/47 could not be observed. These results suggest that the internal stress due to the sputter deposition plays an important roll in the unique characteristics of crystallographic and electrical properties of the epitaxial PZT films.

Magnetoelectric effects of nanoparticulate Pb(Zr0.52Ti0.48)O3–NiFe2O4 composite films

“…3͑a͒, the measured P-E loops had good ferroelectric characteristics: the remnant polarization, saturation polarization, and coercive field at the applied electric field of 800 kV/ cm were 45 C/cm 2 , 60 C/cm 2 , and 275 kV/ cm, respectively. These values are comparable to those of reported PZT films, 12 which indicate that the PZT phase retains its good quality in the composite film. We also performed magnetization versus field ͑M-H͒ measurements using a Quantum Design magnetic property measurement system.…”

Piezoelectric properties of (K,Na)NbO 3 thin films deposited on (001)SrRuO 3/Pt/MgO substrates

“…The lattice parameters of the c-axis increased with increasing potassium concentration in the films, like those of the bulk KNN; however, the KNN thin films show longer c-axes than bulk ones. The reason for the difference in elongation of the clattice parameters between thin films and bulk materials is unclear; however, the same phenomena have been reported for epitaxial PZT films with a thickness of 2.5 ∼ 3.0 µm [9]. So that the dependence on thickness might be examined, lattice constants of the KNN films (x = 0 and 0.16) with a thickness of 2.0 ∼ 2.5 µm were also measured, and the films showed 3.95Å (x = 0) and 3.98Å, respectively.…”

Experimental and theoretical investigations of delamination at free edge of interface between piezoelectric thin films on a substrate

“…After sputtering a thin Ti adhesion layer on a single-crystal silicon (Si) substrate with thickness of 520 lm followed by a Pt layer of 100 nm, (Pb 1Àx La x )TiO 3 (PLT) with x = 0-30% was deposited at 750°C. The PZT layer was then sputtered at 700°C with 180 W rf power by radio-frequency (rf) magnetron sputtering technique (Kanno et al, 1997;Kanno et al, 2003). The resulting thickness of the PZT film was approximately 2.5 lm, which is typical from the viewpoint of MEMS applications as micro-piezoelectric devices.…”