Measurement of spin-diffusion length in sputtered Ni films

The spin-diffusion length of the electron represents a fundamental transport parameter and plays a central role in the development of spintronic devices. While several measurements of the spin-diffusion length in normal metals and in ferromagnetic alloys exist, measurements in elemental ferromagnets (Ni, Fe, Co) have been scarce. We present a novel sample geometry using giant magnetoresistance (GMR) for the measurement of the spin-diffusion length in elemental ferromagnets with weak scattering asymmetry. We report the first measurement of the spin-diffusion length of Ni using an exchanged-biased Permalloy-based spin-valve, Py/Ni/Cu/Py, where the Ni layer acts as a “GMR spoiler” layer when its thickness becomes greater than the spin-diffusion length in Ni.