Specific Resistance and Scattering Asymmetry of Py/Pd, Fe/V, Fe/Nb, and Co/Pt Interfaces

The properties of interfaces between normal (N) and ferromagnetic (F) metals, described by specific resistance, AR* (A = area, R = resistance), and scattering asymmetry, $\gamma $, are of interest to optimize current-perpendicular-to-plane (CPP) magnetoresistance (MR) and current-induced magnetization-switching (CIMS) in nanopillars. Sputtered standard Py/Cu, Co/Cu, and Fe/Cr interfaces have 2AR* $\sim $ 1 f$\Omega $m$^{2}$ and $\gamma \quad \sim $ 0.7. Recently, sputtered F/Al interfaces with F = Py, Co, Fe, and Co(91)Fe(9) were found to have very large 2AR$^{\ast }$ $\sim $ 9 f$\Omega $m$^{2}$, but small $\gamma \quad \le $ 0.1 [1]. In hopes of finding interfaces with both large 2AR* and larger $\gamma $ than for F/Al, we have determined 2AR* and $\gamma $ at 4.2K for sputtered Py/Pd, Fe/V, Fe/Nb, and Co/Pt pairs, where we've matched crystal structures of the F and N metals. We will present our data and our derived values of 2AR* and $\gamma $. [1] N. Theodoropoulou et al., J. Appl. Phys. \textbf{99}, 08G502 (2006); \textit{ibid}., IEEE Trans. on Magn. (Submitted).