Room-Temperature Tunneling Magnetoresistance in Magnetic Tunnel Junctions with a D0 sub(3)-Fe sub(3)Si Electrode

To inform room-temperature spin functionality of D0 sub(3)-ordered Fe sub(3)Si, we explore tunneling magnetoresistance (TMR) effects in magnetic tunnel junctions (MTJs) consisting of Co sub(60)Fe sub(40)/AlO sub(x)/Fe sub(3)Si on Si. We clearly observe reproducible TMR ratios of ~20% at room temperature for all MTJs fabricated. By using Julliere's formula, the room-temperature spin polarization (P) value for D0 sub(3)-ordered Fe sub(3)Si can be roughly estimated to be ranging from 0.18 to 0.45 when we assume the P values from 0.5 to 0.2 for Co sub(60)Fe sub(40). This study reveals that the room temperature P value for D0 sub(3)-ordered Fe Si is relatively small compared with that for Co-based Heusler alloys reported previously.