Transient dynamics through a magnetic tunnel junction*

We present a model study on the time-dependent charge transport through a magnetic
tunnel junction. Magnetic fluctuation in the central region of the tunnel junctions is
modelled as magnons, and its influence on the tunneling is treated as a local bosonic
mode described by the spinless Anderson-Holstein model. Using Keldysh nonequilibrium
Green's function we compute the time dependent current with various type of source
drain bias. Dressed tunneling approximation is used to handle the strong electron-magnon
or other bosonic modes interaction. We analyze the phase diagram of the transient time as
a function of different parameters of the model system, and explore the regions for fast
switching which is useful for device making.