Damping of Magnetization Precession in Perpendicularly Magnetized CoFeB Alloy Thin Films

Abstract

Gilbert damping is investigated in perpendicularly magnetized CoFeB thin films using ferromagnetic resonance and time-resolved magneto-optical Kerr effect. The CoFeB films were deposited on a MgO layer and annealed at different temperatures. The lowest effective damping constant αeff values were 0.017, 0.013, and 0.009 for the films annealed at 250, 300, and 350 °C, respectively; these values were smaller than the values reported previously.