Elliott-Yafet mechanism and the discussion of femtosecond magnetization dynamics

In the past it has been questioned whether the Elliott-Yafet mechanism of spin-flip scattering of electrons at phonons may explain the ultrafast demagnetization of a ferromagnet (mostly Ni) after femtosecond laser excitation. The reason has been that the value of the Elliott-Yafet spin-mixing parameter b² of Ni has not been known and has been taken as the one of Cu (which is the nearest neighbor in the periodic table) which is very small. We present calculations of b² by the ab initio density-functional electron theory for Co, Fe, Ni, Cu, Au, and K. For Co, Fe, and Ni b² is about a factor of 25 larger than the value commonly assumed for Cu. This result should support the Elliott-Yafet mechanism in the discussion of fs magnetization dynamics.