Formation of Texture in Co/Cr Films for Perpendicular Magnetic Recording

Texture formation in sputter deposited Co/Cr films is investigated in dependence on film thickness and substrate temperature by means of electron microscopy, electron diffraction, X-ray diffraction, and magnetic measurements. In films deposited at 350 K film texture forms very rapidly within a transition layer thickness of about 50 nm beginning already in the noncontinuous growth stages below about 10 nm. In films deposited at higher substrate temperatures (up to 550 K) texture formation is much slower combined with a smaller grain size in the continuous film. The corresponding thicker transition layer causes a large in-plane component of magnetization which essentially degrades the suitability of such films for perpendicular magnetic recording. The texture formation is interpreted as a selection process driven by free energy contributions from grain surfaces, interfaces, and boundaries.