Femtosecond laser excitation of multiple spin waves and composition dependence of Gilbert damping in full-Heusler CO_2Fe_(1-x)Mn_xAl films

摘要

Spin-wave dynamics in 30 nm thick CO_2Fe_(1-x)Mn_xAl full-Heusler films is investigated using time-resolved magneto-optical polar Kerr spectroscopy under an external field perpendicular to films. Damon-Eshbach (DE) and the first-order perpendicular standing spin-wave (PSSW) modes are observed simultaneously in four samples with x = 0, 0.3, 0.7, and 1. The frequency of DE and PSSW modes does not apparently depend on composition x, but damping of DE mode significantly on x and reaches the minimum as x = 0.7. The efficient coherent excitation of DE spin wave exhibits the promising application of Co_2Fe_(0.3)Mn_(.07)Al films in magnonic devices.