Effect of Cu/Fe/Co substitution on static and dynamic magnetic properties of Ni-Mn-Sn alloy thin films

Cu or Fe or Co substituted off-stoichiometric Ni-Mn-Sn films of 500 nm thickness were deposited on Si (1 0 0) substrate by dc magnetron sputtering at ambient temperature and then annealed ex situ at 550 °C for 1 h under high vacuum. X-ray diffraction and atomic force microscopy analyses showed that the annealed films exhibited high degree of crystalline order with cubic L21 phase. Magneto-static evaluation of the films established room temperature ferromagnetic order with easy axis of magnetization along the film plane in all the annealed films. The ratio of magnetic resonance and magnetic saturation (Mr/Ms) increased drastically upon Co substitution. The analysis of polar angle dependence resonance field (Hr) and resonance linewidth (ΔH) measurement using resonant cavity FMR technique revealed the presence of negative effective perpendicular magnetic anisotropy (K1) and very low Gilbert damping constant (α) in all the films.