Micromagnetic and magneto-transport simulations of nanodevices based on MgO tunnel junctions for memory and sensing applications

This work provides a systematic simulation study of magnetic tunnel junction (MTJ) nanodevices behavior, consisting of a multilayered stack incorporating an in-plane CoFeB free layer and a synthetic antiferromagnetic CoFe-based pinned layer, and including exchange and interlayer couplings. A finite element tool is used to simulate both the magnetic and magneto-transport behaviors of these MTJ nanopillars with distinct geometries, namely circles with diameter ranging from 20 nm up to 250 nm and ellipses with aspect ratios of 1/2, 1/3 and 1/5, corresponding to sizes from 20×40 nm2 up to 50×250 nm2. This study envisages two clear applications for nanopillars: memory and sensor devices. We address the impact of the nanopillar size on the coercivity and saturation field, as figures of merit for device performance. In particular a competitive sensitivity of 0.15%/Oe is envisaged for sensors with a size of 50×100 nm2. Our results provide a validation of this simulation method as a expedite tool to assist the nanofabrication process.