Ni<sub>80</sub>Fe<sub>20</sub> nanotubes with optimized spintronic functionalities prepared by atomic layer deposition
Maria Carmen Giordano, Simon Escobar Steinvall, Sho Watanabe, Anna Fontcuberta i Morral, Dirk Grundler
Abstract
thin films and nanotubes using nickelocene and iron(iii) tert-butoxide as metal precursors, water as the oxidant agent and an in-cycle plasma enhanced reduction step with hydrogen. We have optimized the ALD cycle in terms of Ni : Fe atomic ratio and functional properties. We obtained a Gilbert damping of 0.013, a resistivity of 28 μΩ cm and an anisotropic magnetoresistance effect of 5.6 % in the planar thin film geometry. We demonstrate that the process also works for covering GaAs nanowires, resulting in permalloy nanotubes with high aspect ratios and diameters of about 150 nm. Individual nanotubes were investigated in terms of crystal phase, composition and spin-dynamic response by microfocused Brillouin Light Scattering. Our results enable NiFe-based 3D spintronics and magnonic devices in curved and complex topology operated in the GHz frequency regime.