Electrical Resistivity in Ferromagnetic TM-Al-O (TM = Fe, Co) Granular Films: Scattering by Spin Waves and Kondo Like Behavior

摘要

We investigate the electrical resistivity of the ferromagnetic granular thin films TM-Al-O (TM = Fe, Co). The resistivity shows T-2 behavior at low temperatures in all metallic samples. This strongly suggests scattering of conduction electrons by thermally excited ferromagnetic spin waves. Logarithmic Kondo like behavior (- log T) in the resistivity and negative magnetoresistivity at low temperatures are observed. With decreasing concentration of transition metal, both the coefficients of the T-2 and log T terms increase.