Micromagnetic Simulations of CoFeB/MgO Perpendicular Stacks for Sensor Applications

CoFeB/MgO thin films are popular materials materials for application in magnetic storage and spintronic devices. In this study, we use micromagnetic simulations to characterize the magnetic properties of CoFeB/MgO thin films devices with perpendicular anisotropy, aiming at optimizing the structures for detection of magnetic fields perpendicular to the plane. We simulate various experimentally achievable combinations of exchange stiffness, interfacial anisotropy, the thicknesses of the CoFeB film and dimensions and aspect ratio of the devices in order to see how is their impact on the magnetic performance. Furthermore, we numerically show that obtaining a low coercivity and low saturation field for thin films in an out-of-plane (OOP) sensing application is impossible without a strong interfacial anisotropy, even if its volumic anisotropy in the OOP axis is arbitrary. These findings provide valuable insights into the magnetic behavior of OOP magnetic systems, in particular based on CoFeB/MgO thin films and could aid in the design of improved sensorial devices.