Determination of the spin-flip time in ferromagnetic SrRuO3 from time-resolved Kerr measurements

We report time-resolved Kerr effect measurements of magnetization dynamics in ferromagnetic SrRuO3. We observe that the demagnetization time slows substantially at temperatures within 15 K of the Curie temperature, which is 150 K. We analyze the data with a phenomenological model that relates the demagnetization time to the spin-flip time. In agreement with our observations, the model yields a demagnetization time that is inversely proportional to T-Tc. We also make a direct comparison of the spin-flip rate and the Gilbert damping coefficient, showing that their ratio is very close to k BTc, indicating a common origin for these phenomena. © 2011 American Physical society.