Manipulation of film quality and magnetic properties of CrO(2) (100) films on TiO(2) substrates with carrier gas and growth temperature

High-quality CrO(2) films were synthesized on TiO(2) (100) substrates at different temperatures using the chemical vapor deposition method in argon or nitrogen atmosphere. It was found that the lower limit for the growth temperature of CrO(2) films can be reduced to 310 or 300 °C when using Ar or N(2) as the carrier gas, respectively. The quality of CrO(2) film on TiO(2) substrate can thus be improved by optimizing growth temperature in a much larger range (310–400 °C in Ar and 300–430 °C in N(2), in contrast with 390–410 °C in O(2)), which is significant for the practical application of CrO(2) films. The best film quality was achieved at 320 °C in either Ar or N(2) atmosphere, at which CrO(2) film has its narrowest orientation distribution and lowest roughness. Compared to films grown in O(2), films grown in Ar were found to have larger saturation magnetizations (M(s)) and magnetic anisotropies, possibly due to numerous O vacancies. Films grown in N(2) are actually N-doped films, and have lower M(s) than those grown in O(2). The Curie temperature (T(c)) was also tuned by the carrier gas and growth temperature. Films grown in Ar or N(2) generally have a higher T(c) value than those grown in O(2). Furthermore, the thermal stability of the films was found to be remarkably improved when using N(2) as the carrier gas.