Spin injection and detection in p-Si channel using highly spin polarized Heusler alloy Co45Ni5Cr25Al25/MgO tunnel contact

Spin injection and detection in non magnetic p-Si semiconductor have been studied in details in Co45Ni5Cr25Al25(CNCA)/MgO/p-Si heterojunction fabricated using Electron Beam Evaporation (EBE) technique. The 3-terminal tunnel contacts in Hanle geometry have been made on the device for transport measurements. The current-voltage characteristics of the junction shows excellent rectifying magnetic diode like behaviour in lower temperature range (below 200 K). The spin accumulation in non magnetic p-Si semiconductor has been observed at different bias current under the applied magnetic field parallel to the film plane in the temperature range of 30-300 K. The Hanle effect is used to control the reduction of spin accumulation by applying magnetic field perpendicular to the carrier spin in the p-Si. The accumulated spin decaying as a function of applied magnetic field for fixed bias current has been recorded. The spin life time (67 pS) and spin diffusion length (227 nm) have been estimated of the heterostructure at 250 K.