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Barium strontium titanate [Ba 0.6 Sr 0.4 TiO 3 or BST (60/40)] thin films were deposited on MgO (100) substrates using pulsed laser deposition. X-ray diffraction (XRD) measurements revealed that the BST thin films had epitaxially grown on the MgO (100) substrates. The surface morphology of the thin films was observed using an atomic force microscope and the grain size was found to be about 100–150 nm. The surface roughness was around 4.9 nm for a 250 nm thick film. The optical transmittance of the BST thin film was measured using a transmission mode ellipsometer. The BST/MgO configuration was highly transparent in the visible region. The optical band gap energy of the BST film, calculated by applying the Tauc relation, was 3.56 eV. Optical waveguide characteristics of the BST (60/40) thin film were determined using a prism coupler. The electro-optic (E-O) properties were measured at 632.8 nm wavelength using a phase modulation detection method. The BST film exhibited a predominately quadratic E-O behavior and the quadratic E-O coefficient was found to be 0.58 × 10 - 17 m 2 /V 2 . [ABSTRACT FROM AUTHOR]

The electrical properties and Raman spectroscopy of [001]-oriented pure lead-free Na0.5Bi0.5TiO3(NBT) and manganese-doped NBT single crystals have been investigated. With the effect of Mn-doping, the remnant polarizationPrhas a great enhancement from 15.2 μC/cm2to 30.0 μC/cm2, and the pyroelectric coefficient is improved significantly from 178 μC/m2K to 241 μC/m2K. The Mn-doping has further altered the domain structure of the crystals, as revealed by piezoresponse force microscopy study. The Raman studies suggest that the substitution effect of Mn ions on B-site cations of the perovskite structure results in enhancement of the performance of the Mn-doped NBT single crystals. [ABSTRACT FROM AUTHOR]

The dielectric tunability of Ba(Zr x Ti 1-x )O 3 (x = 0.20, 0.25, 0.30 and 0.35, respectively) thin films epitaxially grown on MgO (001) single crystal substrates were investigated. The BZT thin films were deposited by means of pulsed laser ablation followed by annealing at 1100°C. X-ray diffraction revealed that the thin films were all well crystallized and epitaxially aligned on the substrate. The in-plane dielectric properties of the BZT thin films were characterized on a network analyzer. It is found that all the films have moderate dielectric constants and good tunability. Comparatively, however, Ba(Zr 0.30 Ti 0.70 )O 3 seems to be the most suitable candidate for making prototype microwave devices due to its largest tunability among all the samples. The typical in-plane dielectric properties of Ba(Zr 0.30 Ti 0.70 )O 3 thin film are: dielectric constant = 240 (at 10 MHz), tunability = 26% (at 1 GHz and under dc bias of 13 MV/m). [ABSTRACT FROM AUTHOR]

Niobium-doped bismuth titanate (Bi 3.5-x/3 Nd 0.5 Ti 3-x Nb x O 12 , x = 0 to 0.09) were prepared using a conventional mixed oxide method, and the effects of Nb doping on the dielectric, ferroelectric, piezoelectric and pyroelectric properties of the ceramics were examined. In general, the doping with Nb decreases the relative permittivity ε, coercive field E c and leakage current density J of the ceramics, while increases the remnant polarization P r , piezoelectric (charge) coefficient d 33 and pyroelectric coefficient p. At 6 mol% Nb-doping level, the ceramic exhibit a large P r (15 μ C/cm 2 ) and a low J (3×10 -8 A/cm 2 ) under an electric field of 75 kV/cm, while its d 33 and p reach a maximum value of 22 pC/N and 129 μ C/m 2 K, respectively. Since the ceramic also has a relatively low ε value of 115 (hence a high value of piezoelectric (voltage) coefficient), it is a potential candidate for sensing applications. [ABSTRACT FROM AUTHOR]

Vinylidene fluoride/trifluoroethylene [P(VDF-TrFE)] copolymers have attracted considerable interest as potential polymer candidates for integrated optics applications because of their good electro-optic and nonlinear optical properties. In this paper, the prism coupling technique was employed to characterize the optical properties of P(VDF-TrFE) 70/30 mol% films. The copolymer films were deposited on Si wafers using the spin coating method and subsequently annealed at 140°C for 2 h. The refractive indices of the copolymer films were measured at 414 nm, 632.8 nm and 1547 nm, respectively. The refractive indices for the TE mode and TM mode, n TE and n TM , decrease slightly with increasing wavelength and their dependence on wavelength can be fitted to the Cauchy formula. Using the inverse Wentzel-Kramers-Brillouin (i-WKB) method, the refractive index along the thickness of the copolymer films was determined and was found to vary only slightly with depth, indicating good optical homogeneity along the film thickness. The scattering losses in the copolymer films at a wavelength of 1547 nm were measured using the moving fibre method and the losses for the TE 0 mode and TM 0 mode were 1.55 dB/cm and 1.47 dB/cm, respectively. [ABSTRACT FROM AUTHOR]

Barium strontium titanate (Ba 0.50 Sr 0.50 )TiO 3 (BST), and barium zirconate titanate Ba(Zr 0.35 Ti 0.65 )O 3 (BZT) thin films on Pt-coated silicon substrates have been prepared by pulse laser deposition. The highly (100)-oriented BST and BZT thin films with nano-sized grains of 15∼⃒25 nm have been characterized by X-ray diffraction, atomic force microscopy and impedance measurements. The dielectric constant and dissipation factor of BST and BZT thin films were 822 and 0.025, 416 and 0.015 at 1 MHz, respectively. The dielectric constant of BST and BZT thin films changes significantly with applied dc bias field and has high tunabilities and figures of merit of 63% and 42, 67% and 45, respectively under an applied field of 250 kV/cm. [ABSTRACT FROM AUTHOR]

In this work, Ba0.5Sr0.5TiO3 thin films were deposited on a LAO substrate by rf magnetron sputtering followed by thermal annealing. XRD spectra revealed good crystallization of the film. The ring resonator electrode pattern consists of feed lines, coupling gaps and the resonator has been deposited by sputtering and patterned by a standard photolithography and wet etching technique. The microwave testing of the device was performed using a network analyzer with a pair of microprobes. The ring resonators were characterized by measuring the scattering parameters in the frequency range of 50 MHz to 20 GHz. It was found that the resonance occurs when the mean circumference of the ring resonator is equal to an integral multiple of the guided wavelength. A commercial electromagnetic simulator, IE3D was used to simulate the S21 spectra and fitted to the experimental results to obtain the relative permittivity of the BST film. Also, it was observed that the resonant frequency shifted when the film thickness was varied. The mechanism responsible for this dielectric behavior has been discussed. [ABSTRACT FROM AUTHOR]

This paper reports on the integration and characterization of Pb(Zr,Ti)O 3 (PZT) thin film on silicon-on-insulator (SOI) wafers. Two perovskite-structured oxide layers, SrTiO 3 and (La,Sr)CoO 3 , were deposited by magnetron sputtering on the SOI to form a template and the bottom electrode. On the buffered SOI, the PZT thin film was deposited by sol-gel and spin coating techniques followed by thermal treatment for crystallization. X-ray diffraction revealed that PZT has a good quality of crystallization and a preferred orientation along the [001]-direction. The electrical measurement indicates that the PZT film on SOI has good ferroelectric and piezoelectric properties. The piezoelectric coefficient of the PZT film was found to be about 80× 10 - 12 m/V. [ABSTRACT FROM AUTHOR]