Surface Anisotropy of Permalloy in NM/NiFe/NM Multilayers
J O. Rantschler, P J. Chen, Anthony S. Arrott, Robert D. McMichael, William F. Egelhoff Jr., Brian B. Maranville
We have measured surface anisotropy in Permalloy (Py) deposited between two layers of normal metal (NM = Ag, Cu, or Ta) by determining the total perpendicular anisotropy using both the frequency and angular dependence of ferromagnetic resonance spectroscopy (FMR). The Py-Ta interface has a surface anisotropy of 0.078 b0.03 mJ/m2 and the Py-Ag and Py-Cu interfaces have surface anisotropies of 0.10 b0.04 mJ/m2. If the surface anisotropy is taken into account on the edges of a 200x100x4 nm3 oval Permalloy element, the switching field is reduced by 15%.