AVS 47th International Symposium
    Magnetic Interfaces and Nanostructures Monday Sessions
       Session MI-MoA

Paper MI-MoA9
Highly Spin-Polarized Chromium Dioxide Thin Films Prepared by Chemical Vapor Deposition from Chromyl Chloride

Monday, October 2, 2000, 4:40 pm, Room 206

Session: Thin Films and Multilayers
Presenter: W.J. DeSisto, University of Maine
Authors: W.J. DeSisto, University of Maine
P.R. Broussard, Covenant College
T.F. Ambrose, Naval Research Laboratory
B.E. Nadgorny, Naval Research Laboratory
M.S. Osofsky, Naval Research Laboratory
Correspondent: Click to Email
Highly spin-polarized materials, and in particular thin films, are central to many magneto-electronic devices. An efficient and controlled chemical vapor deposition (CVD) process for depositing highly spin-polarized, metastable chromium dioxide (CrO@sub 2@) on (100) TiO@sub 2@ substrates has been developed using chromyl chloride (CrO@sub 2@Cl@sub 2@) as a precursor. This precursor is a liquid at room temperature with a vapor pressure adequate for CVD using conventional precursor handling equipment. The films were shiny, black, and approximately 200 nm thick. The spin polarization, as measured by the Point Contact Andreev Reflection (PCAR) technique, was 81± 3%. X-ray diffraction @theta@/2@theta@ scans indicated the films grew completely (100) oriented, in registry with the (100) oriented TiO@sub 2@ substrate. X-ray diffraction @phi@-scans on the CrO@sub 2@ (110) reflection indicated the expected two-fold symmetry, with no evidence of misaligned material. The resistivity at room temperature was 240 @micro@@ohm@cm and decreased to 10 @micro@@ohm@cm at 5K, consistent with metallic behavior. The films were ferromagnetic with a Curie temperature of 395 K and a coercivity of approximately 100 Oe at 298 K. This deposition technique enhances the possibility of fabricating a GMR and/or a tunnel junction device based on CrO@sub 2@, and thus opens up new opportunities in magneto-electronics.