An observable effect of spin inertia in slow magneto-dynamics: Increase of the switching error rates in nanoscale ferromagnets

The Landau-Lifshitz-Gilbert (LLG) equation, used to model magneto-dynamics in ferromagnets, tacitly assumes that the angular momentum associated with spin precession can relax instantaneously when real or effective magnetic field causing is turned off. This neglect of "spin inertia" unphysical and would violate energy conservation. Recently, LLG equation was modified account for inertia effects. consensus, however, seems be such effects unimportant slow take place over time scales much longer relaxation momentum, which typically few fs perhaps ~100 ps ferromagnets. Here, we show there at least one very serious observable effect even magneto-dynamics. It involves switching error probability flipping magnetization a nanoscale ferromagnet an external agent, as field. may ~ns complete strength close threshold value switching, than time, yet felt probability. because ultimate fate trajectory, i.e. whether it results success failure, influenced by what happens first action nutational dynamics due holds sway. Spin increases probability, makes more error-prone. has vital technological significance relates reliability logic memory.