| Photorefractive Tungsten Bronze Materials for Optical Computing |
FEB 97 |
93 pages |
| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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 | The optical tungsten bronze BSTN and BSKNN single crystals were investigated for photorefractive and guided wave optical applications with considerable success. These materials have both high optical figure of merit and low dark conductivity, making them potentially important for pattern recognition and 3-D memory applications. Undoped crystals are advantageous for electrooptic devices such as guided wave for telecommunication and signal processing. Under this effort, advances were made in growth of ... |
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| Integration of Ferroelectric/Semiconductor Thin Films for SLM and Photorefractive Operations |
FEB 97 |
83 pages |
| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
|
| High polarization PZT thin films have been grown on lattice-matched SBN and LAAlO3 substrates. The polarization obtained is the highest to-date, because these films are highly oriented. Because of increased polarization, the optical figure of merit is very high, which will produce compact devices operating at significantly lower voltages in applications such as guided-wave optics, switches and photorefractive memory. |
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| Integration of Ferroelectric/Semiconductor Thin Films for SLM and Photorefractive Applications |
09 AUG 93 |
175 pages |
| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| This report covers work on the integration of ferroelectric and semiconductor materials for SLMs carried out over the period of September 24, 1990, through March 23, 1993, in the Ferroelectric Materials Department of the Rockwell International Science Center under Contract No. F49620-90-C-0084. During this period, significant progress has been made in the growth of highly grain-oriented perovskite PZT and BaTiO3 thin films on lattice matched SBN, SrTiO3 and MgO substrates. ... |
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| Research in High Dielectric Properties of Ferroelectric Materials |
JAN 92 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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 | The magnetron sputtering technique has been used to grow morphotropic phase boundary ferroelectric thin films of tungsten bronze PBKNN and perovskite BaTiO3, KTN and PZT. Film crystallinity was found to be strongly Influenced by substrate temperature, with temperatures of 500-6000C usually required. Single crystal PSKNN films were grown on SBN:60 substrates, whereas grain-oriented films were achieved on (100)-oriented silicon substrates. PLZT films are grain- oriented for (001)-oriented SBN and have ... |
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| Piezoelectric and Ferroelectric Properties of La-Modified and Unmodified Tungsten Bronze Pb(0.6)Ba(0.4)Nb2O6 Dense Ceramics |
91 |
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| Authors:
R. R. Neurgaonkar; J. R. Oliver; J. G. Nelson; L. E. Cross; ROCKWELL INTERNATIONAL THOUSAND OAKS CA
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| As part of a long range project on piezoelectric materials for actuators and sensors, the ceramic densification of ferroelectric tungsten bronze Pb(0.6)Ba(0.4)Nb2O6 (PBN:60), with and without La3+ modification, has been investigated. Samples prepared using pressure during sintering exhibit high densification (> 95%) with improved piezoelectric and polarization properties. Our current best samples show a spontaneous polarization of up to 24 microcoul/sq cm and piezoelectric strain coefficients, d33, of up to ... |
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| Research on Sputtering of Ferroelectric Thin Films |
FEB 90 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| The magnetron sputtering technique has been used to grow morphotropic phase boundary ferroelectric thin films of tungsten bronze PBN:60 and pervoskite PLZT. Film crystallinity was found to be strongly influenced by substrate temperature, with temperatures of 500-600 C usually required. Single crystal PBN:60 films were grown on SBN:60 substrates, whereas grain-oriented films were achieved on (100)-oriented Si substrates. PLZT films are grain-oriented for (001)-oriented SBN and have excellent surface quality ... |
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| Growth of Tungsten Bronze Family Crystals |
MAR 89 |
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| Authors:
R. R. Neurgaonkar; L. E. Cross; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| A systematic investigation of tungsten bronze crystals for electro- optic and photorefractive applications has been carried out successfully. The Sr1-XBaXNb2O6 (SBN) and Ba2-XSrXK1-yNaYNb5o15 (BSKNN) system crystals were grown in optical quality with and without specific impurities whose purpose is to enhance photorefractive coupling and speed. Both SBN and BSKNN crystals appear to be excellent hosts for electro-optic applications, e.g., modulators, waveguides, and spatial light modulators (SLM) and photorefractive applications, e.g., ... |
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| Research on Sputtering of Ferroelectric Thin Films |
JUN 88 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| The magnetron sputting technique has been used to grow ferroelectric thin films of tungsten bronze (T.B.) PBN:60 and SBN:75, and perovskite PLZT. Film crystallinity was found to be strongly influenced by substrate temperature, with temperatures of 500-600 C usually required. Polycrystalline films were grown on quartz, sapphire and glass substrates, whereas oriented crystalline films of PBN:60 and SBN:75 were achieved with SBN:60 substrates, which have a close lattice match. The ... |
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| Research on Crystal and Film Ferroelectric Materials for Optoelectronic Applications |
MAR 88 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| The millimeter wave dielectric behavior of several tungsten bronze ferroelectrics is presented, along with a theoretical evaluation of the origin of the dielectric losses which are shown to arise from polar microdomain fluctuations. Data is also presented for new, La-modified bronze SBN:60 crystals which have very large dielectric constants at room temperature. A comprehensive thermodynamic phenomenology is presented for SBN:60, showing a unique tetracritical phase transition behavior for this ferroelectric. ... |
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| Growth of Tungsten Bronze Family Crystals |
DEC 87 |
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| Authors:
R. R. Neurgaonkar; L. E. Cross; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| The objective of this work is to develop suitable quality and size doped and undoped Strontium(1-x)Barium(x)Niobium(2)Oxide(6) (SBN) single crystals or thin films that can be used in optical device studies. The second objective of this work is to develop a phenomenological model to explain the correlation between the ferroelectric and optical properties and thereby possibly control and optimize the material performance for optical device applications. Keywords: Strontium, Barium, Niobium, Single ... |
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| Growth of Tungsten Bronze Family Crystals |
JUN 87 |
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| Authors:
R. R. Neurgaonkar; L. E. Cross; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| The objective of the present work is to develop suitable quality and size doped and undoped Strontium(1-x)Barium(x)Niobium(2)Oxide(6) (SBN) single crystals or thin films that can be used in optical device studies. The second objective of this work is to develop a phenomenological model to explain the correlation between the ferroelectric and optical properties and thereby possibly control and optimize the material performance for device optical applications. Keywords: Strontium, Barium, Niobium, ... |
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| Research on Millimeter Wave Dielectric Materials |
AUG 86 |
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| Authors:
J. R. Oliver; R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| Much of the early effort in this program was devoted to single crystal strontium barium niobate (SBN), a tungsten bronze with an unusually large room-temperature dielectric response. More recently, other tungsten bronzes such as potassium lithium niobate (KLN) and barium strontium potassium sodium niobate (BSKNN) have been prepared and studied to elucidate the role of unfilled crystallographic sites in influencing dielectric loss. Currently, we are developing preparation techniques for morphotropic ... |
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| Growth of Tungsten Bronze Family Crystals |
JUL 86 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL CANOGA PARK CA
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| The objective of the present work is to develop suitable quality and size Sr(0.6)Ba(0.4)Nb2O6 (SBN) single crystals or thin films that can be used in optical device studies. The second objective of this work is to develop a phenomenological model to explain the correlation between the ferroelectric and optical properties and thereby possibly control and optimize the material performance for device applications. Keywords: Strontium barium niobium oxides, Cerium, Doping, Electrooptics. ... |
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| Growth of Ferro-Electric Tungsten Bronze Epitaxial Thin Films for Electro-Optic Device Applications |
JUN 86 |
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| Authors:
R. R. Neurgaonkar; J. R. Oliver; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| Strontium Barium Biobates:60 doped with Ce and Fe crystals have now been grown with improved optical quality using the Czochralski technique. The liquid phase epitaxial (LPE) growth of SBN:46 on SBN:60 substrate has also been successfully demonstrated, with particularly good results for (100) and (110) film orientations. The recent photorefractive measurements on Ce doped SBN:60 crystals show that the Tungsten Bronze, SBN:60 crystals are superior in many respects to BaTi03 ... |
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| Growth of Tungsten Bronze Family Crystals |
18 MAR 86 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL CANOGA PARK CA
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| The objective of the present work is to develop suitable quality and size Sr(0.6)Ba(0.4)Nb(206) (SBN) single crystals or thin films that can be used in optical device studies. The second objective of this work is to develop a phenomenological model to explain the correlation between the ferroelectric and optical properties and thereby possibly control and optimize the material performance for device applications. Keywords: Strontium barium niobium oxides; Ferroelectric crystals. (aw) ... |
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| Ferroelectric Tungsten Bronze Crystals for Far Infrared Electro-Optic Device Applications |
NOV 85 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL ANAHEIM CA SCIENCE CENTER
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| The primary objective of this research program is to develop for electro-optic and nonlinear optical applications high quality, striation-free crystals of a number of interesting tungsten bronze compositions such as Ba(2-x) Sr(x)K(1-y)Na(y)Nb5O15 (BSKNN), Ba6Ti2Nb8O30 (BTN), and a few compositions which are close to a morphotropic phase boundary, using the Czochralski and edge defined crystal growth techniques. The large transverse and longitudinal electro-optic response obtainable near morphotropic phase boundaries are studied ... |
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| Ferroelectric Tungsten Bronze Bulk Crystals and Epitaxial Thin Films for Electro-Optic Device Applications |
AUG 85 |
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| Authors:
J. R. Oliver; R. R. Neurgaonkar; L. E. Cross; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| Several doped (ce3+Ce4+ and Fe2+/Fe3+) and undoped SBN:60 single crystals have been grown using the Czochralski technique. Optical evaluation shows that Ce-doped crystals have minimum or no striations and are of optical quality, while Fe-doped crystals are highly striated under all growth conditions. Current results suggest that the existence of striations depends strongly on the type of dopant and its location in the structure. Ce-doped SBN:60 crystals currently exhibit excellent ... |
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| Research on the Crystal Growth and Dielectric Properties of High Permittivity Ferroelectric Materials |
JUL 85 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| Millimeter wave measurements on tungsten bronze Sr0.6Ba0.4Nb2O6 (SBN:60) and Ba2-xSrxK1-yNayNb5O15(BSKNN) have shown a strong temperature dependence for permittivity and dielectric loss, with both decreasing at low temperature down to 77K for the electric field parallel to the polar axis. The observed changes in and perpendicular to the polar axis are much less, being only 30-40%. A temperature sensitive peak in the polar has been observed for some samples. First experimental ... |
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| Ferroelectric Tungsten Bronze Bulk Crystals and Epitaxial Thin Films for Electro-Optic Device Applications |
JUL 1984 |
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| Authors:
L. E. Cross; J. R. Oliver; R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| Several doped and undoped SBN:60 single crystals have been grown by the Czochralski technique. Although the quality of doped crystals needs to be improved, they show a considerable enhancement in electro-optic and photorefractive properties, specifically for Ce(3+)-doped SBN:60 crystals. The addition of these impurity species did not change the growth conditions significantly; however, striations were present and became stronger as the concentration of impurity ions increased. Undoped SBN:60 single crystals ... |
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| Ferroelectric Tungsten Bronze Bulk Crystals and Epitaxial Thin Films for Electro-Optic Device Applications |
FEB 1984 |
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| Authors:
R. R. Neurgaonkar; L. E. Cross; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
|
| SBN:50 and SBN:60 crystals have now been grown with improved optical quality using the Czochralski technique with automatic diameter control. The liquid phase epitaxial (LPE) growth of SBN:50 on SBN substrates has also been successfully demonstrated, with particularly good results for (100) and (110) film orientations. Electro-optic measurements on SBN:60 single crystals have shown a high value for r51 of 80 x 10 to the minus 12th power m/v, nearly ... |
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| Single Crystal Growth of Ferroelectric Tungsten Bronze Compositions for SAW Applications |
FEB 1984 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| Ferroelectric tungsten bronze single crystals were grown by the Czochralski technique. The crystals belong to the tetragonal point group 4mm with spontaneous polarization parallel to the 'c' axis. Room temperature dielectric and piezoelectric measurements indicated that the k 15 and d 15 coefficients are significantly larger for these bigger unit cell bronzes as compared to the smaller unit cell bronzes, e.g. SBN, SKN, etc. The results of this study indicated ... |
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| Research on Ferroelectric Materials for Millimeter Wave Application |
AUG 1983 |
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| Authors:
R. R. Neurgaonkar; L. E. Cross; W. F. Hall; W. W. Ho; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| The largest and highest quality single crystals of the tungsten bronze family ferroelectric compositions of the strontium - barium niobate family reported to date were prepared by Czochralski growth techniques. Low frequency dielectric properties show low loss and high permittivity as expected. Accurate high frequency dielectric measurements for several compositions were made in a waveguide geometry from 30 to 100 GHz and the electric field sensitivity of the microwave refractive ... |
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| Ferroelectric Tungsten Bronze Bulk Crystals and Epitaxial Thin Films for Electro-Optic Device Applications |
MAY 1983 |
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| Authors:
R. R. Neurgaonkar; L. E. Cross; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
|
| One -3 cm diameter single crystals of the bronze compositions SBN:50 and SBN:60 have been successively grown. Optical striations in SBN:60 are found to arise from impurities and temperature instability during growth. Improvements in temperature stability, rotation rate, and post-annealing conditions have improved the optical quality considerably. LPE growth of SBN:48 on SBN:60 and SBN:50 single crystal substrates has been successful, with crystal films of 10- 15 micrometers in thickness ... |
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| Research on the Crystal Growth and Dielectric Properties of High Permittivity Ferroelectric Materials |
MAR 1983 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| The systems investigated for potential millimeter wave applications are the stuffed tungsten bronze single crystal BSKNN, and the modified lead niobate ceramics PKLN and PBN. Low frequency and millimeter wave dielectric measurements show these materials to be promising for future applications. The observed high absorptive loss (tan delta approximately 0.2) and rapidly decreasing permittivities at GHz frequencies for these initial samples may be due to piezoelastic coupling to heavily damped ... |
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| Single Crystal Growth of Potassium Lithium Niobate for SAW Applications |
FEB 1983 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA MICROELECTRONICS RESEARCH AND DEVELOPMENT CENTER
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| We have successfully demonstrated the growth of good quality, crack- free medium size KLN single crystals using the Czochralski method, with dielectric and piezoelectric properties comparable or superior to the best known bronze composition SBN. However, we have been unable to grow large (>1 cm diameter) KLN crystals suitable for SAW characterization without considerable cracking. Therefore, in pursuit of alternative bronze compositions with the potential for large crystal growth, we ... |
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| Research on Ferroelectric Materials for Millimeter Wave Application |
DEC 1982 |
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| Authors:
R. R. Neurgaonkar; L. E. Cross; W. F. Hall; W. W. Ho; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
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| This technical report presents the results of the second six months of a research program on ferroelectric materials for phase control applications in millimeter wave radar systems. Originally a one-year program, this effort has been extended to fifteen months to take advantage of materials development activities in related programs. The major accomplishments in the current period include growth and preparation of several ferroelectric materials, and high frequency dielectric characterization of ... |
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| Temperature Compensated Piezoelectric Materials. |
SEP 1982 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA MICROELECTRONICS RESEARCH AND DEVELOPMENT CENTER
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| A full phenomenological model has been developed to predict the dielectric, piezoelectric and elastic compliances and their temperature behavior for bronze structure ferroelectrics. The model is based on an extension of the Landau: Ginsburg: Devonshire phenomenology which includes the diffuse nature of the curie transition at TC. Sixth rank electrostrictive coupling terms have been found necessary to adequately describe the paraelectric phase above the curie temperature; these terms do not ... |
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| Research on Ferroelectric Materials for Millimeter Wave Application |
MAY 1982 |
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| Authors:
R. R. Neurgaonkar; L. E. Cross; W. F. Hall; W. W. Ho; ROCKWELL INTERNATIONAL THOUSAND OAKS CA MICROELECTRONICS RESEARCH AND DEVELOPMENT CENTER
|
| A one-year research program has been undertaken to determine whether certain selected ferroelectric materials can be used to obtain effective phase control in millimeter wave radar systems. This investigation is an outgrowth of earlier work at Rockwell which included the first demonstration of microwave phase modulation in strontium barium niobate (SBN) single crystals. 1 The present study combines materials development and millimeter wave characterization to investigate the feasibility of achieving ... |
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| Research on the Crystal Growth and Dielectric Properties of High Permittivity Ferroelectric Materials |
APR 1982 |
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| Authors:
R. R. Neurgaonkar; W. W. Ho; W. F. Hall; ROCKWELL INTERNATIONAL THOUSAND OAKS CA MICROELECTRONICS RESEARCH AND DEVELOPMENT CENTER
|
| Single crystals of Sr2KNb5015 (SKN), approximately 5-8 mm in diameter and 10-20 mm long, have successfully been grown by the Czochralski technique. The crystal has ferroelectric tetragonal tungsten bronze structure with a curie temperature of about 150 C. The dielectric and electromechanical coupling constants for this crystal have been established: the polar axis dielectric constant, K33 exceeds 20,000 at the curie temperature while the coupling constants are k33 = 0.52 ... |
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| Temperature Compensated Piezoelectric Materials |
JAN 1982 |
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| Authors:
R. R. Neurgaonkar; L. E. Cross; ROCKWELL INTERNATIONAL THOUSAND OAKS CA MICROELECTRONICS RESEARCH AND DEVELOPMENT CENTER
|
| From the electrostriction measurements on SBN crystals, it was found that the fourth order electrostrictive coupling terms are not adequate to fully describe the paraelectric phase above Curie temperature, and hence six rank coupling terms are needed; the electrostrictive coupling terms do not change markedly with cation substitution. Results of SAW measurements on the SBN:60 crystal showed that this composition possesses temperature-compensated orientations and it is similar to other best-known ... |
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| Temperature Compensated Piezoelectric Materials |
JUL 1981 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA MICROELECTRONICS RESEARCH AND DEVELOPMENT CENTER
|
| From the electrostriction measurements on SBN crystals, it was found that the fourth order electrostrictive coupling terms are not adequate to fully describe the parelectric phase above curie temperature, and hence six rank coupling terms are needed; the electrostrictive coupling terms do not change markedly with cation substitution. Several flux systems have successfully been developed for the liquid phase epitaxy work of SBN compositions. The work is successful, and it ... |
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| Research in LPE of Doped LiNbO3 and LiTaO3 Thin Films |
JUN 1981 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA ELECTRONICS RESEARCH CENTER
|
| The crystal chemical approach has been shown to be successful in improving the temperature stability of ferroelectric LiNbO3 phase. LiNbO3 films doped with cations that are larger than Li+ and Nb5+, e.g., Na+, Na+ + Ta5+, Ag+, Co2+ + Zr4+, etc., have successfully been grown by the liquid phase epitaxial (LPE) technique using the vanadium containing flux systems. X-ray diffraction studies indicate that the films grown from the vanadium containing ... |
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| Temperature Compensated Piezoelectric Materials |
JAN 1981 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA ELECTRONICS RESEARCH CENTER
|
| From the electrostriction measurements on SBN crystals, it was found that the fourth order electrostrictive coupling terms are not adequate to fully describe the paraelectric phase above Curie temperature, and hence six rank coupling terms are needed; the electrostrictive coupling terms do not change markedly with cation substitution. Several flux systems have successfully been developed for the liquid phase epitaxy work of SBN compositions. The work is successful, and it ... |
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| Temperature Compensated Piezoelectric Materials |
AUG 1979 |
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| Authors:
R. R. Neurgaonkar; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
|
| A literature survey of the known tungsten bronze structural family has been completed and compiled. A phenomenological model based on the Gibb's energy functions to explain the nature of temperature compensation in the bronze family has currently been developed. This work has been extended to specific bronze phases such as the tetragonal SBN and the orthorhombic PBN. Several flux systems have successfully been established for the liquid phase epitaxy (LPE) ... |
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| Temperature-Compensated Piezoelectric Materials |
JAN 1979 |
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| Authors:
R. R. Neurgaonkar; L. E. Cross; ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
|
| During the first and second quarters of the present contract, an initial literature survey of all known tungsten-bronze compounds was completed. Preliminary formulation of the Gibb's energy function for ferroic materials to describe the phase transitions has been accomplished. Apparatus to perform LPE growth of tungsten-bronzes has been constructed and several suitable flux systems for the growth of strontium-barium-niobate (SBN) films have been found. From an analysis of the chemistry ... |
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| Synthesis and Crystal Chemistry of Oxysulfides with the Garnet Structure, |
30 AUG 1973 |
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| Authors:
R. R. Neurgaonkar; William B. White; PENNSYLVANIA STATE UNIV UNIVERSITY PARK MATERIALS RESEARCH LAB
|
| In a search for new ternary materials with potential suitability for 10.6 micrometer window applications, the sulfur analogs of the garnet structure were investigated. Pure sulfur end-member garnets cannot be synthesized under ambient pressures. A series of oxysulfide garnets with sulfur to oxygen ratios of 7.5/4.5 were discovered. These have the general formula (Ln3(VIII)Me2(VI)Me3(IV)O4.5S7.5) where Ln is any rare earth except La(3+) and Me is a variety of 2+, 3+, ... |
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Reports by Author
