Highly spin-polarized chromium dioxide thin films prepared by chemical vapor deposition from chromyl chloride

Highly spin-polarized chromium dioxide (CrO2) thin films were deposited on ~100! TiO2 substrates by chemical vapor deposition using chromyl chloride as a precursor. The spin polarization, as measured by the point contact Andreev reflection technique, was 8163%. X-ray diffraction u/2u scans indicated the films grew completely ~100! oriented, in registry with the ~100! oriented TiO2 substrate. X-ray diffraction f scans on the CrO2 ~110! reflection indicated the expected twofold symmetry, with no evidence of misaligned material. The resistivity at room temperature was 240 mV cm and decreased to 10 mV cm at 5 K, consistent with metallic behavior. The films were ferromagnetic with a Curie temperature of 395 K and a coercivity of ;100 Oe at 298 K. The use of chromyl chloride as a precursor resulted in efficient and controlled CrO2 film growth. © 2000 American Institute of Physics. @S0003-6951~00!04125-5#