Electric field driven solid state reactions—microscopic investigation of moving phase boundaries in the system MgO/MgIn2O4/In2O3

2003 ◽  
Vol 5 (24) ◽  
pp. 5530-5535 ◽  
Author(s):  
C. Korte ◽  
N. D. Zakharov ◽  
D. Hesse
Keyword(s):  
Solid State ◽  
Electric Field ◽  
Microscopic Investigation ◽  
Solid State Reactions ◽  
Phase Boundaries

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.

The formation of copper aluminate by solid-state reaction

1991 ◽  
Vol 6 (9) ◽  
pp. 1958-1963 ◽  
Author(s):  
David W. Susnitzky ◽  
C. Barry Carter
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Substrate Surface ◽  
Alumina Substrate ◽  
Solid State Reactions ◽  
Phase Boundaries ◽  
Copper Aluminate ◽  
Scanning Electron

Solid-state reactions between bulk samples of copper oxide and alumina have been studied using scanning electron microscopy and electron microprobe analysis. Both CuAl2O4 and CuAlO2 were found to form during reactions in air at 1100 °C between CuO powder and single-crystal alumina substrates. The relative position of the CuAl2O4 and CuAlO2 layers was observed to depend on the crystallographic orientation of the surface of the alumina substrate: CuAl2O4 formed in contact with (0001) alumina substrates while CuAlO2 formed when the alumina substrate surface was (110). Faceted Cu–aluminate/alumina phase boundaries were observed to develop when single-crystal alumina rods were reacted with CuO, although the interfaces invariably tended to be wavy.

Use of Pt Markers in the Study of Solid-State Reactions in the Presence of an Electric Field

1998 ◽  
Vol 4 (2) ◽  
pp. 158-163 ◽  
Author(s):  
Matthew T. Johnson ◽  
Shelley R. Gilliss ◽  
C. Barry Carter
Keyword(s):  
Thin Film ◽  
Solid State ◽  
Electric Field ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Solid State Reactions ◽  
Single Crystal Substrate ◽  
Fine Scale ◽  
Initial Location ◽  
Crystal Substrate

The use of Pt to mark the initial location of heterophase boundaries in solid-state reactions was extended to investigate the motion of interfaces during a thin-film solid-state reaction between In2O3 and MgO in the presence of an electric field. The Pt markers were prepared by sputtering a thin Pt film onto a single-crystal substrate. The resulting multilayer was then heated prior to thin-film deposition to de-wet the Pt film and thus form an array of small, isolated particles. These particles serve as fine-scale markers for tracking the motion of interfaces. However, there are certain situations in which the markers can move with the interface.

Interfaces in high-Tc superconducting oxides

1989 ◽  
Vol 47 ◽  
pp. 178-179
Author(s):  
C. Barry Carter ◽  
Lisa A. Tietz
Keyword(s):  
Solid State ◽  
Grain Boundaries ◽  
Superconducting Phase ◽  
Solid State Reactions ◽  
High Angle ◽  
Phase Boundaries ◽  
High Tc ◽  
Superconducting Material ◽  
First Case ◽  
Superconducting Oxides

Interfaces in high-Tc superconducting oxides are influential during both the processing of bulk materials and the growth of thin epitactically aligned layers. In the first case, the formation of the superconducting phase involves the movement of phase boundaries during the solid-state reaction, while in the second, the phase boundary is formed as the superconducting material grows on the single-crystal substrate. Having formed the superconducting material, the superconducting phase will, in general, contain a large number of grain boundaries varying from the simple twin boundaries which can be produced during the cubic-to-tetragonal transformation, to low-angle grain boundaries, special high-angle grain boundaries, other high-angle grain boundaries and phase boundaries due to incomplete or on-going solid-state reactions. During the course of this presentation, recent results on these topics will be reviewed, paying particular attention to the more widely studied material, YBa2Cu3O6+x.The importance of grain boundaries in high-Tc superconducting oxides has been firmly established by the systematic analysis of Dimos et al who have shown that the misorientation of the grains in layers of YBa2Cu3O6+x which had been grown on polycrystalline SrTiO3 substrate varies with the relative misorientation between the grains.

Solid-State Reactions in Model Oxide Systems

1996 ◽  
Vol 453 ◽  
Author(s):  
Matthew T. Johnson ◽  
Paul G. Kotula ◽  
Ryan S. Thompson ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Reaction Rates ◽  
Oxide System ◽  
Solid State Reactions ◽  
Diffusion Control ◽  
Phase Boundaries ◽  
Oxide Systems ◽  
Fe Oxide ◽  
Kinetics Of

AbstractThe kinetics of thin-film solid-state reactions have been investigated in two model spinel forming oxide systems, NiO/Al2O3 and MgO/Fe2O3. In the NiO/Al2O3 system, thin-films of epitactic NiO were reacted with (0001), , and orientated Al2O3 (corundum). The kinetics of the spinel forming reaction for this system were found to be linear-parabolic in nature. Additionally, it was found that the kinetics of the spinel-forming reaction varied by nearly two orders of magnitude between the fastest and slowest diffusion couples. The substrate determines the orientation of the overlayers and thereby the structure of the phase boundaries. In the MgO/Fe-oxide system, thin films of epitactic Fe oxide were reacted with {001} MgO. The kinetics of this spinel forming reaction were parabolic in nature, indicative of diffusion control. In contrast to the N1O/Al2O3 system, the movement of phase boundaries are not the step controlling the reaction rate, but rather the diffusion of one of the cations across the reaction layer. In comparing the reaction rates for the two systems the activation energy for the formation of the spinel product in the MgO/Fe-oxide system was found to be almost a factor of 4 lower in comparison to the NiO/Al2O3 system.

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).

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