The Effect of an Electric Field on the Reaction Between Oxides

1998 ◽  
Vol 4 (S2) ◽  
pp. 594-595
Author(s):  
Matthew T. Johnson ◽  
C. Barry Carter
Keyword(s):  
Electric Field ◽  
Applied Electric Field ◽  
Elevated Temperatures ◽  
Ionic Current ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Diffusion Couples ◽  
Charged Species ◽  
Thin Film Diffusion ◽  
Reaction Processes

It is well known that diffusion in ionic materials occurs primarily by the movement of charged species. Therefore, an applied electric field can provide a very large driving force for mass transport. In the present study, thin films of In2O3 and Fe2O3 have been deposited on (001) and (111) MgO using pulsed-laser deposition (PLD). These thin-film diffusion couples have then been reacted in an applied electric field at elevated temperatures. The electric field directly influences the diffusion of the cations in the constitutive layers. Through the use of both transmission (TEM) and scanning (SEM) electron microscopy, diffusion couples reacted either with and without an electric field have been analyzed to examine the effect that an induced ionic current can have on solid-state reaction processes.The apparatus for reacting the diffusion couples in a field has been described elsewhere. The diffusion couples were characterized in cross-section by SEM and TEM techniques.

Electric-Field Effects on Reactions Between Oxides

1997 ◽  
Vol 481 ◽  
Author(s):  
Matthew T. Johnson ◽  
Shelley R. Gilliss ◽  
C. Barry Carter
Keyword(s):  
Solid State ◽  
Electric Field ◽  
Elevated Temperatures ◽  
Ionic Current ◽  
Reaction Rates ◽  
Solid State Reactions ◽  
Interfacial Stability ◽  
Electric Field Effects ◽  
Thin Film Diffusion ◽  
Microscopy Techniques

ABSTRACTThin films of In2O3 and Fe2O3 have been deposited on (001) MgO using pulsed-laser deposition (PLD). These thin-film diffusion couples were then reacted in an applied electric field at elevated temperatures. In this type of solid-state reaction, both the reaction rate and the interfacial stability are affected by the transport properties of the reacting ions. The electric field provides a very large external driving force that influences the diffusion of the cations in the constitutive layers. This induced ionic current causes changes in the reaction rates, interfacial stability and distribution of the phases. Through the use of electron microscopy techniques the reaction kinetics and interface morphology have been investigated in these spinel-forming systems, to gain a better understanding of the influence of an electric field on solid-state reactions.

solid-state reactions in the presence of an electric field

1997 ◽  
Vol 3 (S2) ◽  
pp. 623-624
Author(s):  
Matthew T. Johnson ◽  
C.Barry Carter
Keyword(s):  
Solid State ◽  
Electric Field ◽  
Elevated Temperatures ◽  
Reaction Rates ◽  
Laser Deposition ◽  
Solid State Reactions ◽  
Interfacial Stability ◽  
Interface Morphology ◽  
Charged Species ◽  
Microscopy Techniques

It is well known that diffusion in ionic materials occurs primarily by the movement of charged species. Therefore, an electric field should provide a very powerful driving force for mass transport. In the present study, solid-state reactions, in the presence of an electric field, have been carried out between thin films of In2O3 and bulk monocrystalline MgO ﹛001﹜. In solid-state reactions of this type, reaction rates and interfacial stability are affected by the transport properties of the reacting ions. by applying an electric field across the sample, at elevated temperatures, the reaction rates and interfaces are affected as a result of ionic conductivity. Through the use of electron microscopy techniques the reaction kinetics and interface morphology have been investigated, in this spinel forming system, to gain a better understanding of the influence of an electric field on interface morphology and solid-state reactions.The reaction couples used in this study were produced by means of pulsed-laser deposition (PLD).

Pulsed Laser Deposition of BaxSr1−xTiO3 Films on MgO, LaAlO3 and SrTiO3 for Tunable Microwave Applications

1998 ◽  
Vol 541 ◽  
Author(s):  
Wontae Chang ◽  
James S. Horwitz ◽  
Won-Jeong Kim ◽  
Jeffrey M. Pond ◽  
Steven W. Kirchoefer ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Electric Field ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Dielectric Constants ◽  
Laser Deposition ◽  
Film Stress ◽  
Donor Acceptor ◽  
Bst Films

AbstractSingle phase BaxSr1−xTiO3 (BST) films (∼0.5-7 μm thick) have been deposited onto single crystal substrates (MgO, LaAlO3, SrTiO3) by pulsed laser deposition. Silver interdigitated electrodes were deposited on top of the ferroelectric film. The room temperature capacitance and dielectric Q (1/tanδ) of the film have been measured as a function of electric field (≤80 kV/cm) at 1 - 20 GHz. The dielectric properties of the film are observed to strongly depend on substrate type and post-deposition processing. After annealing (≤1000° C), it was observed that the dielectric constant and % tuning decreased and the dielectric Q increased for films deposited onto MgO, and the opposite effect was observed for films deposited onto LaA1O3. Presumably, this change in dielectric properties is due to the changes in film stress. Very thin (∼50 Å) amorphous BST films were successfully used as a stress-relief layer for the subsequently deposited crystalline BST (∼5000 Å) films to maximize % tuning and dielectric Q. Films have been deposited from stoichiometric targets and targets that have excess Ba and Sr. The additional Ba and Sr has been added to the target to compensate for deficiencies in Ba and Sr observed in the deposited BST (x=0.5) films. Films deposited from compensated targets have higher dielectric constants than films deposited from stoichiometric targets. Donor/acceptor dopants have also been added to the BST target (Mn, W, Fe ≤4 mol.%) to further improve the dielectric properties. The relationship between the dielectric constant, the dielectric Q, the change in dielectric constant with electric field is discussed.

Substrate Effects in In-Situ Growth of Perovskites by Pulsed Laser Deposition

1991 ◽  
Vol 243 ◽  
Author(s):  
K. F. Etzold ◽  
R. A. Roy ◽  
K. L. Saenger
Keyword(s):  
Pulsed Laser Deposition ◽  
Lead Zirconate Titanate ◽  
Elevated Temperatures ◽  
Pulsed Laser ◽  
Interface Layer ◽  
Dielectric Constants ◽  
Laser Deposition ◽  
In Situ Growth ◽  
Substrate Dependence

AbstractIn this study we report on in-situ growth of lead zirconate titanate (PbZr1-xTixO3, PZT) and strontium titanate (SrTiO3, STO) films by pulsed laser deposition at 248 nm. Films were deposited in an oxygen background at elevated temperatures on a variety of substrates including MgO(l00), Pt(100)/MgO(100), Pt(111)/MgO(111), Pt(110)/MgO(110), Pt(111)/SiO2/Si, and Pt(111)/glass.Deposited films were characterized by Rutherford Backscattering Spectroscopy (RBS), x-ray diffraction (XRD), and electrical (dielectric constant and leakage) measurements. A strong substrate dependence was found for both the fraction of pyrochlore (Pb2Zr2-xTixO7) phase in the PZT films, and the STO film dielectric constants. The origin of the substrate dependence is discussed with regard to nucleation and interface layer cffects, and the chemistry of the relevant materials.

Switching Kinetics of Pulsed Laser Deposited Epitaxial PZT Films

1998 ◽  
Vol 526 ◽  
Author(s):  
M. Yamazato ◽  
A. M. Grishin ◽  
Y. Yamagata ◽  
T. Ikegami ◽  
K. Ebihara
Keyword(s):  
Electric Field ◽  
Domain Switching ◽  
Switching Time ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Pzt Films ◽  
Frequency Independent ◽  
Kinetics Of ◽  
Coercive Electric Field ◽  
Ferroelectric Switching

AbstractWe have fabricated epitaxial PbZr0.52Ti0.48O3 (PZT, 40~1200 nm)/YBa2Cu3O7-x (YBCO, 400 nm) film ferroelectric/superconductor heterostructures on the single-crystal neodymium doped yttrium monoaluminate [YAlO3+1%Nd2O3] and MgO substrates by KrF pulsed laser deposition technique. The dielectric constant of 950 and loss tangent δ of 0.04 have been found to be frequency independent in the range 100 Hz to 100 kHz while electric resistivity ρ (150 kV/cm) is of 6×1011 Ω·cm, remnant polarization and coercive field are 32 μC/cm2 and 43 kV/cm, respectively. Fast ferroelectric switching kinetics with characteristic switching time around 50 ns has been observed. Universal electric field and temperature dependencies of switching time as well as film thickness dependence of coercive electric field have been observed and correspond to ferroelectric needle-like domain switching.

scholarly journals Pulsed laser deposition of a PBN:65 morphotropic phase boundary thin film with large electrostriction

Open Physics ◽  
2005 ◽  
Vol 3 (2) ◽  
Author(s):  
Xi Yang ◽  
Andrew Beckwith ◽  
Mikhail Strikovski
Keyword(s):  
Thin Film ◽  
Electric Field ◽  
Phase Boundary ◽  
Pulsed Laser Deposition ◽  
Morphotropic Phase Boundary ◽  
Incident Light ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Epitaxial Thin Films ◽  
Electric Field Induced Strain

AbstractWe deposited epitaxial thin films of Morphotropic Phase Boundary (MPB) Pb0.65Ba0.35Nb2O6 (PBN:65) on MgO substrates using pulsed laser deposition. Afterwards, a novel transmission optical experiment was developed to measure the electric field-induced bending angle of the thin film sample using a divergent incident light. From which the electric field-induced strain was obtained, and it was used to calculate the electrostrictive constant of the PBN thin film. The result is 0.000875 μm2/V2, and it is consistent with what we measured in the reflection experiment

Pulsed Laser Deposition of SrBi2Ta2O9 Thin Films for Nonvolatile Memory Applications

1995 ◽  
Vol 397 ◽  
Author(s):  
S. Werner ◽  
D. Thomas ◽  
S.K. Streiffer ◽  
O. Auciello ◽  
Angus I. Kingon
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Nonvolatile Memory ◽  
Elevated Temperatures ◽  
Sol Gel ◽  
Pulsed Laser ◽  
Hysteresis Loops ◽  
Laser Deposition ◽  
Polarization Electric Field ◽  
Memory Applications

ABSTRACTFerroelectric SrBi2Ta2U9 (SBT) thin films were synthesized by pulsed laser deposition (PLD) on platinized silicon substrates held at different substrate temperatures, from targets with different compositions. It was necessary to anneal films deposited at low temperature (525°C) at elevated temperatures in an oxygen atmosphere in order to achieve properties comparable to SBT thin films grown by the sol-gel technique. Polarization – electric field hysteresis loops showed saturation in the 2-5 V range with a remnant polarization 2Pr = 8-13 µC/cm2. Capacitors showed negligible fatigue up to 1010 switching cycles.

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