  We report the first experimental demonstration of electrical spin injection,
transport and detection in bulk germanium (Ge). The non-local magnetoresistance
in n-type Ge is observable up to 225K. Our results indicate that the spin
relaxation rate in the n-type Ge is closely related to the momentum scattering
rate, which is consistent with the predicted Elliot-Yafet spin relaxation
mechanism for Ge. The bias dependence of the nonlocal magnetoresistance and the
spin lifetime in n-type Ge is also investigated.
