Half-metallic CrO2 thin films on Pt/TiO2/SiO2/Si substrates by chemical vapor deposition

We report difference of growth mechanism of half-metallic CrO2 thin films deposited by chemical vapor deposition method on preferentially oriented (111) and (200) Pt/TiO2/SiO2/Si substrates. The CrO2 thin films grown on (111) Pt/TiO2/SiO2/Si substrate were (200) oriented, and highly crystalline rectangular grains were observed. On the other hand, grown on (200) Pt/TiO2/SiO2/Si substrate, the CrO2 thin films were (110) oriented, and wedge-shaped grains were observed. To study the orientational dependence of magnetic properties of CrO2 thin films, ferromagnetic domains were observed with a magnetic force microscope at room temperature and orientational dependences of magnetization were observed using a superconducting quantum interference device magnetometer. While the ferromagnetic domains of both films showed in-plane ferromagnetic easy-axis resulting from shape anisotropy as well as orientation of an easy axis along the in-plane film direction, magnetic domains showed a marked contrast difference at domain boundaries resulting from the different surface topographies. (C) 2004 American Institute of Physics.