Effect of magnetic field in rf sputtering on the crystal orientation and magnetic properties of Co-Cr perpendicular anisotropy films

Abstract

Co–23‐wt. %‐Cr alloy films with thicknesses of 0.3 to 2.5 μm were deposited using a conventional rf diode sputtering system when a magnetic field Hs less than 90 Oe is applied during deposition. As H_s increases, the hcp c‐axis orientation normal to the film plane develops and the half‐angle width of the rocking curve of the (002) line Δθ₅₀ reaches to 3.5 deg at H_s more than 40 Oe. The development of the orientation is strongly related to the concentration of O in the films, which is lower in the films deposited in a magnetic field than those in a nonmagnetic field. The magnetic properties such as perpendicular coercive force H_c⊥ and saturation magnetization M_s strongly depend on the substrate temperature rather than H_s.