Switching Field Variation in MgO Magnetic Tunnel Junction Nanopillars: Experimental Results and Micromagnetic Simulations (original) (raw)

The switching field dependence on the size of nanometric magnetic tunnel junctions was studied. CoFe/Ru/CoFeB/MgO/CoFeB nanopillars were fabricated down to 150 300 nm and characterized, revealing a squared transfer curve with a sharp transition between magnetic states. A micromagnetic finite element tool was then used to simulate the magnetic behavior of the studied nanopillar. The simulations indicated a single-domain like state at remanence, also displaying a sharp transition between parallel/antiparallel free-layer configurations. Overall, the experimentally measured switching fields were smaller than those obtained from simulations. Such trend was consistent with the presence of a particular free layer profile, signature of the two angle etching step used for pillar definition. Further decrease of experimental was attributed to local defects and thermal activated processes. This study was able to validate this particular simulation tool for the control of the nanofabrication process.