The role of Pt underlayer on the magnetization dynamics of perpendicular magnetic anisotropy Pt/Co2FeAl0.5Si0.5/MgO

We investigate the role of Pt on the magnetization dynamics of Pt/Co2FeAl0.5Si0.5/MgO with perpendicular magnetic anisotropy using the time resolved magneto-optic Kerr effect. Pt/Co2FeAl0.5Si0.5/MgO shows ultrafast magnetization dynamics comparable to 3d ferromagnets and can be fully demagnetized. The demagnetization time tau(d) similar to 0.27 ps and magnetic heat capacity are independent of the Pt underlayer, whereas the value of the electron-phonon coupling time tau(e) similar to 0.77 ps depends on the presence of the Pt layer. We further measure the effective damping alpha(eff) similar to 1 that does not scale as the inverse demagnetization time (1/tau(d)), but is strongly affected by the Pt layer. Published by AIP Publishing.