Abstract

We present results on the magnetoresistance of the system Ni/Al2O3/Si/Al2O3/Ni fabricated in lateral nanostructures. The substrate n-type Si is a nondegenerated semiconductor with a doping level of 10(15) cm(-3). The results are presented between 11 and 30 K, where the electrical resistivity of the semiconductor varies about 4 orders of magnitude. The reduction of magnetoresistance at 30 K is consistent with the standard theory for spin injection between a metal and a semiconductor. By fitting the data with , the diffusion condition, as a function of the channel length t (N) , where the magnetoresistance takes place, we deduced the values of spin diffusion length L (SD) and spin lifetime tau (s) .