Microstructural Development Of thin CoCrTa Films on Cr Underlayers

Abstract

ABSTRACTThe structure of 2.8 – 60nm thick films of CoCrTa sputtered onto a 50nm Cr underlayer at 250°C was studied using atomic resolution microscopy. The Cr grows with a (200) orientation and the CoCrTa grows epitaxially with the [0002] axis in the film plane. The thinnest films have a discontinuous microstructure with several CoCrTa nuclei forming on each Cr grain, with slight misalignment from the exact Pitsch-Schrader orientation relation. The CoCrTa grains coalesce as the film thickness exceeds lOnm and there is evidence for stacking faults at all film thicknesses. For most films the magnetic switching volumes are of similar size to the physical grain volume, suggesting that the entire grain volume participates in magnetic switching.