Conditions for efficient spin injection from a ferromagnetic metal into a semiconductor - art. no. 184420

We adapt the spin accumulation model of the perpendicular transport in meta llic magnetic multilayers to the issue of spin injection from a ferromagnet ic metal (F) into a semiconductor (N). We show that the problem of the cond uctivity mismatch between F and N can be solved by introducing a spin depen dent inter-face resistance (tunnel junction preferably) at the F/N interfac es. In the case of a F/N/F structure, a significant value of the magnetores istance can be obtained if the junction resistance at the F/N and N/F inter faces is chosen between two threshold values depending on the resistivity, spin diffusion length and thickness of N. The problem is treated for variou s geometries (vertical or lateral F/N/F structures).