  We use the time-resolved magneto-optical Kerr effect (TRMOKE) to measure the
local temperature and heat flow dynamics in ferromagnetic SrRuO3 thin films.
After heating by a pump pulse, the film temperature decays exponentially,
indicating that the heat flow out of the film is limited by the film/substrate
interface. We show that this behavior is consistent with an effective boundary
resistance resulting from disequilibrium between the spin and phonon
temperatures in the film.
