Conduction Electron Scattering and Spin-Flipping at Sputtered Co/Ni Interfaces

TL;DR

This study quantifies conduction electron scattering and spin-flipping at sputtered Co/Ni interfaces using CPP-MR measurements, providing specific resistance values and a spin-flipping parameter relevant for spintronic applications.

Contribution

It provides the first quantitative measurements of interface-specific resistances and spin-flipping parameters at sputtered Co/Ni interfaces, aligning with theoretical calculations.

Findings

Co/Ni interface specific resistance for spin-up electrons: 0.03 f-ohm-m^2

Co/Ni interface specific resistance for spin-down electrons: 1.00 f-ohm-m^2

Interface spin-flipping parameter delta: 0.35

Abstract

Current-perpendicular-to-plane magnetoresistance (CPP-MR) measurements let us quantify conduction electron scattering and spin-flipping at a sputtered ferromagnetic/ferromagnetic (F1/F2 = Co/Ni) interface, with important consequences for CPP-MR and spin-torque experiments with perpendicular anisotropy. We use ferromagnetically coupled ([Ni/Co]xn)Ni multilayers, and Py-based, symmetric double exchange-biased spin-valves (DEBSVs) containing inserts of ferromagnetically coupled ([Co/Ni]xn)Co or ([Ni/Co]xn)Ni multilayers, to derive Co/Ni interface specific resistances AR(Co/Ni)(Up) = 0.03 (+0.02)(-0.03) f-ohm-m^2 and AR(Co/Ni)(down) = 1.00 +/- 0.07 f-ohm-m^2, and interface spin-flipping parameter delta(Co/Ni) = 0.35 +/- 0.05. The specific resistances are consistent with our no-free-parameter calculations for an interface thickness between 2 and 4 monolayers (ML) that is compatible with expectations.