Preparation and structural characterization of sputtered CoO, NiO, and Ni sub 0. 5 Co sub 0. 5 O thin epitaxial films
- Department of Physics and Center for Magnetic Recording Research 0401, University of California, San Diego, La Jolla, California 92093-0401 (United States)
- Department of Materials Science and Mineral Engineering, University of California, Berkeley, California 94720 (United States)
Single phase CoO, NiO, and Ni{sub 0.5}Co{sub 0.5}O epitaxial films have been prepared by reactive sputtering onto {l angle}0001{r angle} {alpha}--Al{sub 2}O{sub 3} substrates maintained at 373 K. Epitaxy was confirmed by x-ray diffraction (XRD) and high resolution electron microscopy (HREM) techniques. XRD experiments indicate that these monoxide films are cubic and contain rotation twins with the twin axis parallel to {l angle}111{r angle}. Lattice parameters for the CoO and NiO films are 0.4254{plus minus}0.0001 nm and 0.4173{plus minus}0.0006 nm, respectively, and agree with published values for the corresponding bulk oxides. The lattice parameter 0.4220{plus minus}0.0001 nm for the Ni{sub 0.5}Co{sub 0.5}O film lies between those of CoO and NiO and suggests that the mixed oxide film is compositionally homogeneous. Cross-sectional HREM images of the Ni{sub 0.5}Co{sub 0.5}O specimen show {Sigma}3(1{bar 1}2) twin boundaries perpendicular to the oxide-substrate interface. The twin regions are approximately 30 nm in size and are uniformly distributed throughout the film. The epitaxial orientation of the monoxide films with respect to the substrate can be summarized by the relationships (111) monoxide //(0001) {alpha}--Al{sub 2}O{sub 3}, (1{bar 1}0) monoxide //(1{bar 1}00) {alpha}--Al{sub 2}O{sub 3}, and (11{bar 2}) monoxide //(11{bar 2}0) {alpha}--Al{sub 2}O{sub 3}.
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 5653407
- Journal Information:
- Journal of Materials Research; (United States), Vol. 6:12; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COBALT OXIDES
SPUTTERING
NICKEL OXIDES
THIN FILMS
EPITAXY
ELECTRON MICROSCOPY
LATTICE PARAMETERS
TEMPERATURE RANGE 0273-0400 K
TWINNING
X-RAY DIFFRACTION
CHALCOGENIDES
COBALT COMPOUNDS
COHERENT SCATTERING
DIFFRACTION
FILMS
MICROSCOPY
NICKEL COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SCATTERING
TEMPERATURE RANGE
TRANSITION ELEMENT COMPOUNDS
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication
360202 - Ceramics
Cermets
& Refractories- Structure & Phase Studies