The magnetic properties of cobalt films produced by glancing angle deposition

The magnetic properties of columnar cobalt films fabricated by glancing angle deposition were investigated. Varying the azimuthal rotation speed and polar angle of incidence of the vapor flux produces films with different microstructures. The magnetic anisotropies and squareness ratio between perpendicular and in-plane hysteresis loops are measured for various films and found to have a weak dependence on the azimuthal rotation speed of the substrate at the polar angle of 75°. The squareness ratio is strongly affected by the variation of the polar angle of incidence of the vapor flux. At an azimuthal rotation speed of 0.092 rev/s and polar angle of 83°, the Co film is composed of well-separated columns with the packing fraction of 0.3. The hysteresis loops of this film exhibit a perpendicular anisotropy with the squareness ratio of 1.6. The X-ray diffraction spectrum shows that the Co columns possess a strong (21¯1¯2) preferred orientation, which indicates that the perpendicular anisotropy is from shape anisotropy and not from crystalline anisotropy