Abstract: A seed layer stack with a uniform top surface having a peak to peak roughness of 0.5 nm is formed by sputter depositing an amorphous layer on a smoothing layer such as Mg where the latter has a resputtering rate 2 to 30× that of the amorphous layer. The uppermost seed (template) layer is NiW, NiMo, or one or more of NiCr, NiFeCr, and Hf while the bottommost seed layer is one or more of Ta, TaN, Zr, ZrN, Nb, NbN, Mo, MoN, TiN, W, WN, and Ru. Accordingly, perpendicular magnetic anisotropy in an overlying magnetic layer is substantially maintained during high temperature processing up to 400° C. and is advantageous for magnetic tunnel junctions in embedded MRAMs, spintronic devices, or in read head sensors. The amorphous seed layer is SiN, TaN, or CoFeM where M is B or another element with a content that makes CoFeM amorphous as deposited.

Abstract: In one aspect, a magnetic data storage device comprises a template layer, an underlayer, and a magnetic recording layer. The template layer includes a patterned array of protruding features. The underlayer is formed on the patterned array of protruding features of the template layer. The underlayer includes an array pattern of protruding features that aligns with the patterned array of protruding features of the template layer. The magnetic recording layer is formed on the underlayer. The magnetic recording layer includes columnar grains of magnetic material separated by grain boundaries of non-magnetic material, with each columnar grain being on a protruding feature of the array pattern of the underlayer, and the grain boundaries being in trenches between the protruding features of the array pattern of the underlayer.