Microstructure, texture and magnetic coupling parameters of Ir-Mn-based magnetic tunnel junction

Spin-valve magnetic tunnel junctions (SV-MTJs) with the structure: substrate Si(1 0 0)/SiO2 47 nm/ buffer layers /IrMn 12 nm/CoFe 15 nm/Al-O 1.4 nm/NiFe 3 nm/Ta 5 nm were prepared with four different buffers: (a) Cu 25 nm, (b) Ta 5 nm/Cu 25 nm, (c) Ta 5 nm/Cu 25 nm/Ta 5 nm/Cu 5 nm and (d) Ta 5 nm/Cu 25 nm/Ta 5 nm/NiFe 2 nm/Cu 5 nm in order to investigate crystal texture of the MTJs. The junctions were characterized by XRD θ-2θ scans and rocking curve (ω scans). The multilayer stack is textured in columnar-like fashion, which produces roughness. The texture and the roughness modified strongly the tunnel magnetoresistance (TMR), interlayer Neel and the exchange bias coupling fields in the SV-MTJs. The design of buffer layers allows to optimize the exchange coupling and tunneling parameters for magnetoelectronics devices