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Magnetic transparent conducting oxide film and method of making

United States Patent

July 13, 2004
View the Complete Patent at the US Patent & Trademark Office
Pacific Northwest National Laboratory - Visit the Technology Commercialization Program Website
Cobalt-nickel oxide films of nominal 100 nm thickness, and resistivity as low as 0.06 have been deposited by spin-casting from both aqueous and organic precursor solutions followed by annealing at C. in air. Films deposited on sapphire substrates exhibit a refractive index of about 1.7 and are relatively transparent in the wavelength region from 0.6 to 10.0 .mu.m. They are also magnetic. The electrical and spectroscopic properties of the oxides have been studied as a function of x=Co/(Co+Ni) ratio. An increase in film resistivity was found upon substitution of other cations (e.g., Zn.sup.2+, Al.sup.3+) for Ni in the spinel structure. However, some improvement in the mechanical properties of the films resulted. On the other hand, addition of small amounts of Li decreased the resistivity. A combination of XRD, XPS, UV/Vis and Raman spectroscopy indicated that NiCo.sub.2 O.sub.4 is the primary conducting component and that the conductivity reaches a maximum at this stoichiometry. When x<0.67, NiO forms leading to an increase in resistivity; when x>0.67, the oxide was all spinel but the increased Co content lowered the conductivity. The influence of cation charge state and site occupancy in the spinel structure markedly affects calculated electron band structures and contributes to a reduction of p-type conductivity, the formation of polarons, and the reduction in population of mobile charge carriers that tend to limit transmission in the infrared.
Windisch, Jr.; Charles F. (Kennewick, WA), Exarhos; Gregory J. (Richland, WA), Sharma; Shiv K. (Honolulu, HI)
Battelle Memorial Institute (Richland, WA)
09/ 972,237
October 4, 2001
This invention was made with Government support under Contract DE-AC0676RLO1830 awarded by the U.S. Department of Energy. The Government has certain rights in the invention