Elemental imaging of CoCrTa longitudinal magnetic recording media
The present work investigated a 60 nm thick magnetic layer of Cog4Cri2Ta4 that was d.c. magnetron sputtered at 250°C in 5 mtorr of argon onto a NiP-coated A1 substrate having a 70 nm thick Cr seed layer, Fig. 1. A strong in-plane c-axis crystallographic texture and relatively large grain size makes this an ideal sample to study the effect o f grain boundary character on the Cr segregation kinetics. The lattice fringes and stacking faults from HCP basal planes in Fig. 2 reveal both random angle grain boundaries as well as 90° boundaries. Plan-view samples for EFTEM were prepared by back-thinning through the A1 substrate using standard dimpling and ion milling to isolate the Cog4Cri2Ta4 magnetic layer.