Magnetic Properties of Orthogonal Magnetic Tunnel Junction Made by IrMn- and PtMn-based Synthetic Antiferromagnet

Magnetic Properties of Orthogonal Magnetic Tunnel Junction Made by IrMn- and PtMn-based Synthetic Antiferromagnet

In this reported study, we looked into the magnetic properties of orthogonal magnetic tunnel junction (MTJ) structures usingsynthetic antiferromagnet (SAF) based on IrMn and PtMn. The free layer of the MTJ was prepared by Co40Fe40B20 withperpendicular magnetic anisotropy (PMA). The increase in the purity of sputtering Ar gas helped give a thinner magnetic deadlayer and larger coercivity in the free layer. When using IrMn as an AFM layer, the ferromagnetic layer showed good pinningeffects even at as-deposited conditions. However, using PtMn as an AFM layer needs annealing for the pinning effect. The thinfilms displayed more coercivity and exchanged bias after higher temperature annealing. Furthermore, PtMn deposited at a lowersputtering rate, exhibited better magnetic properties. In-plane magnetic field annealing produced an increased exchange bias butcaused the free layer to lose the perpendicular magnetic anisotropy in the MTJ structure. An additional annealing without-fieldwas performed to recover the PMA of the free layer in the MTJ.