Magnetoresistance in magnetic tunnel junctions with amorphous electrodes

Magnetic tunnel junctions (MTJs) with amorphous CoFeB and Co₂MnSi electrodes were fabricated and examined. In the case of [Co₉₀Fe₁₀]_100-xB_x, the x=32% boron addition reduces the magnetization by 30% compared to Co₉₀Fe₁₀, yet the reduction of the tunnel magnetoresistance (TMR) is over 95%. On the contrary, in the case of Co_(100-x-y)Mn_xSi_y, although net magnetization is very small at room temperature, the TMR can be as large as 7%. The character of each metalloid (boron and silicon) could be responsible for the peculiar behavior to each system.