Evaluation of Gilbert damping in half metals

According to Kambersk\'{y}'s spin torque correlation model of Gilbert damping [1,2], precessional damping in magnetic systems occurs through a combination of spin-flip exciations and orbital excitations. In half-metallic systems, Gilbert damping is expected to be reduced because of the absence of spin-flip scattering. This makes half-metals interesting potential candidates for information storage technologies especially for use in CPP/GMR read head devices and spin-torque MRAM. Using a combination of first principle calculations to predict the band structure for the half-metal of interest and an extended H\"{u}ckel tight binding model we calculate and discuss the Gilbert damping within the spin torque correlation model for different half-metallic structures, including the Heusler alloys Co$_{2}$MnSi, Co$_{2}$MnGe. [1] V. Kambersk\'{y}, Czech. J. Phys. B \textbf{26}, 1366 (1976). [2] B. Heinrich, D. Fraitov\'{a} and V. Kambersk\'{y}, Phys. Stat. Sol. \textbf{23}, 501 (1967).