  The asymptotic behavior of switching time as a function of current for a
uniaxial macrospin under the effects of both spin-torque and thermal noise is
explored analytically by focusing on its diffusive energy space dynamics. The
scaling dependence ($I\rightarrow 0$, $<\tau\propto\exp(-\xi(1-I)^2)$) is shown
to confirm recent literature results. The analysis shows the mean switching
time to be functionally independent of the angle between the spin current and
magnet's uniaxial axes. These results have important implications for modeling
the energetics of thermally assisted magnetization reversal of spin transfer
magnetic random access memory bit cells.
