Large Tunnel Magnetoresistance of Full-Heusler CoFeAISi Alloy Granular Films

摘要

The tunnel magnetoresistance (TMR) and the structure of full-Heusler CoFeAISi (CFAS_-Al_2O_3 granular films have been investigated. It was found that the most part of the film was in discontinuous layers after annealing at 673 K. A maximum MR ratio of about 18% was obtained at room temperature under a magnetic field of 8kOe. The X-ray diffraction pattern of the film exhibited a weak peak of CFAS(220) and/or MgO(200) at about 45°, and a halo-like pattern with two peaks within the range 20-30°. These results suggest that the high MR ratio observed is related to the existence of granules with high spin polarization.