Download or read book Comparison of Microwave Dielectric Properties of Between 001 and 011 Ferroelectric Ba 1 x Sr x TiO3 Thin Films Grown by Pulsed Laser Deposition written by Seung Eon Moon and published by . This book was released on 2003 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of anisotropic dielectric properties of ferroelectric Ba(1-x)Sr(x)TiO3 (BST) films on the characteristics of phase shifter have been studied in microwave regions at room temperature. Ferroelectric BST films with (001) and (011) orientation were epitaxially grown on (001) and (011) MgO substrates, respectively, by pulsed laser deposition method. The structures of BST films were investigated using x-ray diffraction measurement. The microwave properties of orientation engineered BST films were investigated using coplanar waveguide transmission lines that were fabricated on BST films using a thick metal layer by photolithography and etching process. The measured differential phase shift and insertion loss (S sub 21) for (011) BST films are larger than those for (001) BST films. Dielectric constants of the ferroelectric BST films are calculated from the measured S sub 21 using a modified conformal-mapping model.
Download or read book Materials Issues for Tunable RF and Microwave Devices III Volume 720 written by Steven C. Tidrow and published by . This book was released on 2002-08-09 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Challenges facing the implementation of an affordable tunable RF and microwave device technology are discussed in these papers from an April 2002 meeting. Materials issues and devices are examined, with information on new tunable materials, issues of preparation and optimization of bulk and think film properties, material and surface characterization, evaluation of material loss and loss mechanisms, and effects of microstructure. At the device level, phase shifters are discussed and a new device concept for variable true time delay versus phase shift is introduced. At the system level, a paraelectric lens is used to demonstrate electronic beam steering of an antenna. Tidrow is affiliated with the US Army Research Laboratory. Annotation copyrighted by Book News, Inc., Portland, OR
Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 2092 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1996 with total page 944 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ba1xSrxTiO3 Based Thin Films for Next Generation Devices written by and published by . This book was released on 2004 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past several years. there has been a tremendous growth and development of thin film deposition technology in the electronics industry. Ferroelectric thin films have been recognized for their unique dielectric properties and appear to be desirable for tunable microwave device applications. Among the most promising candidates for such applications are Ba(1-x)Sr(x)TiO(3)(BST) and BST-based thin films. In this work, pure BST and acceptor doped BST-based thin films were fabricated on (100) MgO substrates via pulsed laser deposition. X-ray diffraction. in conjunction with the atomic force microscope. was used to analyze the film crystallinity and surface morphology. The dielectric properties were characterized at both 100 kHz and 20 GHz. The metal-insulator-metal capacitor configuration was used to attain the dielectric properties at 100 kHz, and the microwave measurements, $11 reflection parameters. were achieved via interdigitated capacitor design with Au/Ag top electrodes. The parallel resistor-capacitor models were used to determine the microwave capacitance and Q factors, and the permittivity was calculated using a modified conformal-mapping partial-capacitance method using the dimension of the capacitors. Our results demonstrated that the low frequency and microwave frequency dielectric properties were strongly influenced by the film composition. Specifically. the Mg doping served to lower the dissipation factor. permittivity. and tunability of the BST based films at both frequencies. This work demonstrates that the BST based thin films possessed excellent microstructural. structural. and dielectric properties. The structure-process- property correlations of the pulsed laser deposited BST and acceptor doped BST-based thin films are discussed in detail.
Download or read book Ceramic Abstracts written by and published by . This book was released on 1998 with total page 1040 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structural and Dielectric Properties of Ba sub 0 6 r sub 0 4 TiO sub 3 Thin Films written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a systematic study of the structural and dielectric properties of barium strontium titanate, Ba{sub 0.6}Sr{sub 0.4}TiO3 (BST-0.4), films grown by pulsed laser deposition on LaAlO3 and MgO substrates. By optimizing the processing conditions, choosing appropriate substrate materials, and constructing layered architectures, we have successfully deposited BST-0.4 films on both LaAlO3 and MgO substrates with large dielectric nonlinearity and low dielectric loss. X-ray diffraction and transmission electron microscopy analyses reveal that the dielectric tunability and the dielectric loss are closely related to the crystallinity of the BST-0.4 films. We have also observed that a small variation of D value, defined as the ratio of in-plane lattice constant/out-of-plane lattice constant, can result in a significantly large change of dielectric properties of the BST films.
Download or read book Microwave Dielectric Spectroscopy of Ferroelectric Thin Films written by Beomjin Kim and published by . This book was released on 2003 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: We devised a measurement method of microwave dielectric constants of dielectric thin films without applying electrodes. The method uses a rectangular waveguide in which the dielectric thin films prepared on a substrate are filled vertically at the center. The frequency dependence of S-parameter measured by network analyzer enables us to calculate the dielectric constant and loss factor of the films at the microwave region through simulation. We prepared Ba(0.6)Sr(0.4)TiO3 thin films on (001) MgO single crystal substrate by pulsed laser deposition (PLD), and determined their dielectric constant and loss factor at ^10GHz using this method.
Download or read book Structure Property Relationships in W Doped Ba Sr TiO 3 Thin Films Deposited by Pulsed Laser Deposition on 001 MgO written by N. Navi and published by . This book was released on 2003 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ba(x)Sr(1-x)TiO3 films (BST) with x=0.5, 0.6, 0.7, containing 1% W, were grown by pulsed laser deposition on MgO (001) substrates in an oxygen pressure from 3 to 500 mTorr, at a substrate temperature of 720 C. The crystal structure of the film, as determined from x-ray diffraction, was fit to a tetragonal distortion of a cubic lattice having two in-plane lattice parameters. The in and out-of-plane lattice parameters c, a, a', and lattice distortion (a/c and a'/c) were calculated from the positions of the measured BST reflections ((004), (024) and (224)). The dielectric properties of the film at 2 GHz were measured using gap capacitors deposited on top of the dielectric film, at room temperature. For all compositions, as a function of the oxygen deposition pressure, a peak in the change in the dielectric constant, as a function of an applied electric field (0 - 80 kV/cm), was observed for films deposited in 50 mTorr of oxygen. Unlike the pure BST, the dielectric Q was insensitive to the oxygen deposition pressure. The largest Kappa-factor (KAPPA=(epsilon(0)-epsilon(V) x Q(0)) for films deposited, from Ba(0.5)Sr(0.4)TiO3 target were observed in a film that had a minimum in-plane strain, where a^a'.
Download or read book Deposition and Properties of Ferroelectric Pb Sr TiO3 Thin Films for Room Temperature Tunable Microwave Devices written by Shiwei Liu and published by . This book was released on 2004 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study of the Nonlinear Dielectric Properties of Ba1 subscript X Sr subscript X TiO3 Films by Pulsed Laser Deposition written by Yan Fan and published by . This book was released on 2000 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics Briefs written by and published by . This book was released on 1993 with total page 1420 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ferroelectric Thin Films written by and published by . This book was released on 1998 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ferroelectric Thin Films X Volume 688 written by Materials Research Society. Meeting and published by . This book was released on 2002-05 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: The MRS Symposium Proceeding series is an internationally recognised reference suitable for researchers and practitioners.
Download or read book Processing Microstructure and Microwave Dielectric Properties of Tunable Ba Sr TiO3 Thin Films written by Hui Du and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Investigation Into Controlling the Growth Modes of Ferroelectric Thin Films Using Pulsed Laser Deposition and RHEED written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin film ferroelectricss are widely considered for tunable microwave applications, the reduced small dimensions leading to low tuning voltages. The incipient ferroelectric strontium titanate is an ideal solution for tunable microwave devices, particularly in conjunction with high temperature superconductors. It has no spontaneous polarisation yet possesses a large permittivity at low temperatures that is sensitive to an electric field bias with relatively low loss. For such applications it is essential to use a low loss substrate such as magnesium oxide. In general, thin films have less favourable dielectric properties compared with their bulk counterparts due to differences in microstructure. strontium titanate films on MgO substrate prove difficult to grow due to the high lattice mismatch and issues connected with chemical incompatibility at the film/substrate interface. It has been shown here that it is possible to engineer the growth mode of this system, altering the strain and the defect concentration. These are both known factors influencing the dielectric properties of thin films. Reflection high energy electron diffraction (RHEED) in combination with interval pulsed laser deposition (PLD) has been used to achieve a two dimensional, layer-by-layer growth mode. Crucial to this was the deposition of a unit-cell thick titanium dioxide buffer layer on the surface, the deposition of which was also controlled by RHEED. The growth mode and microstructure of films grown using standard PLD with and without the buffer layer and films grown by interval PLD with and without the buffer layer have been compared by analysis of the RHEED data and transmission electron microscopy. This is the first time layer-by-layer growth has been achieved in this highly-mismatched epitaxial systems. The results point the way towards control of defects in oxide thin films from which microstructure-property relationships may be more clearly determined.
Download or read book Life Cycle Testing of Ba x Sr 1 x TiO3 Ferroelectric Thin Films in a Tunable Microwave Device written by NASA Glenn Research Center and published by . This book was released on 2000 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
