  The temperature dependence of magneto current in the spin spin valve
transistor system is theoretically explored based on phenomenological model.
  We find that the collector current strongly depends on the relative
orientation of magnetic moment of ferromagnetic metals due to spin mixing
effect. For example, the collector current is decreasing in the parallel case
with increasing temperature, and it is increasing in anti-parallel
configuration. We then obtain decreasing magneto current with increasing
temperature. The result accords with the experimental data in qualitative
manner. This phenomenological model calculations suggest that spin mixing
effect may play an important role in the spin valve transistor system at finite
temperature.
