Structural and magnetic properties of CoCrPt perpendicular media grown on different buffer layers

The influence of buffer layer characteristics on the structural and magnetic properties of CoCrPt perpendicular media has been investigated. Thin (∼10-15 nm) buffer layers consisting of Ta/Ru, Ta/Hf, or amorphous (CoCrPt)Ta₂₅ produced media layers having high perpendicular coercivity of nearly 3 kOe, but the coercivity was only 1.7 kOe when using a Ta/Ti buffer. X-ray diffraction rocking curves showed the highest degree of (0002) texture for the Ta/Ru buffer. In-plane diffraction indicated that the Ta/Ru buffer also had the smallest lattice mismatch (5.6%) with the CoCrPt. Cross-sectional transmission electron microscopy showed that the Ta/Ru buffer promoted local epitaxy with the media layer. Amorphous transition regions were observed at the interfaces between the media and the Ta/Hf and Ta/Ti buffer layers. Some small CoCrPt grains were observed at the interface with the amorphous CoCrPtTa buffer.