Magnetic Properties of Amorphous Ta/CoFeB/MgO/Ta Thin Films on Deformable Substrates with Magnetic Field Angle and Tensile Strain

Abstract

Recently, cobalt iron boron (CoFeB) thin films have been widely investigated to apply to magnetic sensors, due to their high magnetic moment, anisotropy, and stability. However, most of these studies are conducted on rigid silicon substrates. For more diverse applications of magnetic sensors and angle sensors, it is important to explore the properties of ferromagnetic thin films grown on non-rigid deformable substrates. Here, using representative deformable substrates such as polyimide (PI), polyethylene naphthalate (PEN) and polydimethylsiloxane (PDMS) that can be bent or stretched, we report experimental comparison of in-plane magnetic field angle-dependent properties of the amorphous Ta/CoFeB/MgO/Ta thin film which is grown on those deformable substrates. We investigate effects of substrate roughness, tensile stress, characteristics of deformable substrates, and sputtering process on the change of magnetic properties like coercive field (Hc), remanence over saturation magnetization (Mr/Ms), and their biaxial characteristics. This work presents unconventional foundations for exploring deformable magnetic sensors capable of detecting magnetic field angle.