Properties Of PLZT Films Research Articles

Influence of Film Thickness on Optical Properties of PLZT Thin Films Derived from MOD Method

PLZT (9/65/35) thin films on sapphire (001) substrates with thickness of 0.1 ~ 0.9 µm were prepared by a metal-organic decomposition (MOD) process. All the films present highly (110)-preferred orientation independent of the film thickness. The microstructure of the films was investigated. The influence of film thickness on optical properties of PLZT films was examined and analyzed. As the film thickness is increased, the absorption edge of the film is shifted to longer wavelength; the optical band gap Eg is increased slightly. The refractive index at 510nm determined from optical transmission spectra also shows an increasing tendency as film thickness increasing. Great stress aggregated during the film preparing process is thought to be an important reason which results in the variations of optical properties of the films with different thickness.

Effect of Polyvinylpyrrolidone Molecular Weight on the Critical Thickness, Crystallization, Densification and Properties of PLZT Films

ABSTRACTPLZT 9.5/65/35 ceramic films were prepared from the sol-gel solutions containing the stress-relaxing agent of polyvinylpyrrolidone(PVP) with the molecular weight of 40000, 360000 and 630000 (abbreviated as PVP40, PVP360 and PVP630) respectively. It is found that PVP40 can increase the critical thickness of the PLZT films to 0.22μm(compared with the critical thickness of 0.077μm in case of without PVP) and PVP360 and PVP630 can increase the critical thickness up to 0.49μm and 0.93μm individually. With the molecular weight of PVP increasing, the perovskite formation in the PLZT films was improved but the morphology of the films tended to be nano-porous. The films modified by PVP360 can be densified by optimizing the heat treatment conditions. When pyrolyzed at 600°C and then annealed at 700°C, the one-coating films with the thickness of 0.5μm were dense and exhibited a very slim hysteresis loop with the remnant polarization of 5.96×10−4μC/cm2 and coercive field of 21.51kV/cm, and a transmittance of around 90% and above in the wavelength of 450nm∼900nm.

MICROWAVE DIELECTRIC PROPERTIES FOR (Pb,La)(Zr,Ti)O3 THIN FILMS ON MgO (001) SUBSTRATE GROWN BY CHEMICAL SOLUTION DEPOSITION

ABSTRACT Polycrystalline (Pb,La)(Zr,Ti)O3 (PLZT) films were deposited on MgO (001) single crystal substrates using chemical solution deposition method. Structural properties of PLZT films were investigated using X-ray diffractometer. The dielectric properties of PLZT films were investigated under the dc bias field of 0−40 V using interdigital capacitors (IDC) device fabricated by photolithography and etching process. The small signal dielectric properties of PLZT films were calculated by modified conformal mapping the reflection scattering coefficient data measured using an HP 8510C vector network analyzer in 1–20 GHz at room temperature. The IDC device based on polycrystalline PLZT film exhibited about 40% and 8 of capacitance tunability with dc bias variation of 40 V and dielectric quality factor with no dc bias, respectively.

Crystalline and optical properties of PLZT films prepared by pulsed laser deposition

The PLZT (3/66/34), PLZT (3/46/54), PLZT (9/65/35) and PLZT (28/0/100) thin films were deposited on MgO (100), Sapphire (0001) and fused silica substrates by using pulsed KrF excimer laser deposition technique. The conventional in-situ and 2-step heating processes were utilized to facilitate the synthesis of a large area of uniform PLZT thin film. Pure perovskite phase can be obtained only under very narrow process conditions, the highly textured PLZT films can be easily obtained by in-situ heating process. For PLZT (28/0/100) material, epitaxial films were successfully coated on MgO (100) substrates by 600°C in-situ and RTA 650°C 2-step heating processes. The latter was found to possess higher refractive index and lower extinction coefficient.

Ferroelectric properties of (PbxLa1−x)(ZryTi1−y)O3 films prepared by two-step pulsed laser deposition process

A two-step pulsed laser deposition process has been successfully applied for growing the (PbxLa1−x)(ZryTi1−y) O3, PLZT, thin films. These films exhibit good ferroelectric characteristics (Pr=18 μC/cm2; E c=80 kV/cm; J L≤0.2 μA/cm2), whenever crystalline SrRuO3 materials were used as buffer layers. However, the electrical properties of PLZT films were markedly degraded whenever the amorphous SrRuO3 or (La0.5Sr0.5)CoO3 layer was used as buffer layer.

Effect of Characteristics of SrRuO3 Buffer Layer on the Ferroelectric Properties of (Pb0.97La0.30)(Zr0.66Ti0.34)O3 Thin Films

AbstractA two-step pulsed laser deposition (PLD) process, including PLD at a substrate temperature lower than 150°C and rapid-thermal-annealing (RTA) at around 550°C (30 s), has been successfully applied for growing (Pb0.97La0.03)(Zr0.66Ti0.034)0.9875O3, PLZT, thin films. Interdiffusion between layers is pronouncedly suppressed due to the presence of the SrRuO3 layer, which markedly improves the electrical properties of PLZT films. The PLZT films thus obtained exhibit large remanent polarization P,=19 µC/cm2 (with coercive force Ec=78 kV/cm), low leakage current density J11≤8 × 1O−6 A/cm2 (up to 400 kV/cm) and fatigue free characteristics.

Dielectric and Pyroelectric Characteristics of Plzt (9.5/65/35) Relaxor Thin Films

AbstractFerroelectric relaxor thin films of lead lanthanide zirconate titanate (PLZT) (9.5/ 65/35) have been deposited by the laser ablation technique onto metallized silicon and lanthanum aluminate substrates. The dielectric and pyroelectric properties of PLZT films and their temperature dependencies have been investigated in some detail in an evaluation of their potential as prospective pyroelectric infrared (IR) detector materials. The temperature at which the dielectric constant of a PLZT film reaches its peak is different from that for the peak pyroelectric coefficient. A lower dielectric constant at which the pyroelectric peak appears contributes to a high figure of merit for PLZT films, so that it is competitive with its ceramic counterpart, as well as with Pb(Mg1/3Nb2/3)O3 (PMN) relaxor ferroelectric ceramic.

Preparation and properties of (Pb,La)(Zr,Ti)O3 thin films by metalorganic chemical vapor deposition

Lanthanum-modified lead zirconate titanate (PLZT) thin films have been grown on Pt/MgO(100) and Pt/SiO2/Si substrates at 650 °C by metalorganic chemical vapor deposition using Pb(C2H5)4, La(DPM)3, Zr(DPM)4 and Ti(i − OC3H7)4 as the source materials. The properties of PLZT films were investigated as a function of the La content in a range of 0–15 at.% with a composition ratio of Zr/(Zr+Ti)<0.5. The films were of a single perovskite structure, and highly oriented to the c axis of the tetragonal phase on a Pt/MgO(100) substrate. The films were transformed from tetragonal to nearly cubic as the La content was increased. The films were colorless and transparent, and the surface morphology became smoother through an La addition. The relative dielectric constants increased as the La content was increased up to about 5 at.%. The remanent polarizations were 25–30 μC/cm2, and the coercive field decreased from 53 to 30 kV/cm as the La content was increased in the films having Zr/Ti=40/60.

Preparation and properties of PLZT films from metallo-organic precursors

Abstract Crack free and dense PLZT (8/65/35) films 0.4 to 2.5 μm thick were prepared by spinning a solution of metallo-organic compounds of lead, lanthanium, zirconium and titanium onto sapphire substrates, and firing and annealing the films in air in the range 600 to 850°C. These firing temperatures resulted in films with grain sizes from 0.2 to 1.2 μm. Films fired at 650°C had a dielectric constant of 1800 and a dissipation factor of 2% at 1 kHz, and a spontaneous polarization of 5 μC/cm2. The linear and quadratic electro-optic coefficients were 30 × 10−12 m/V and 50 × 10−18 (m/V)2, respectively.