On the variation of magnetic anisotropy in Co/Pt(111) on silicon oxide

摘要

The structural properties and magnetic anisotropy of Pt/Co/Pt trilayers grown on thermally oxidized (Si/SiO_2) and naturally oxidized silicon (Si/Si_(OX)) are presented. Although similar substrates and identical preparation conditions are used distinct differences in the structural composition are found which stem from the Pt seed layer created via ion assisted sputtering. While for thermal oxidized Si a Pt/Co/Pt trilayer is formed, for systems grown on naturally oxidized Si a complex PtSi alloy formation within the seed layer is observed as a consequence of the high ion energies of ion assisted sputtering. The composition of the PtSi alloy varies along the growth direction with a low Si content at the interface to Co and the lattice constant is similar to bulk Pt. The latter provides a much higher magnetic interface anisotropy constant compared to Pt/Co/Pt on thermal oxidized Si of about 0.9 mJ/m~2 which is comparable to the highest values found for MBE grown Co on single crystalline Pt(111).