Oersted-field-induced switching of a ferromagnet on a Si substrate via localized dielectric breakdown of the native SiO2 layer

Abstract

The phenomenon of dielectric breakdown is employed for switching of magnetization in ferromagnetic (FM) metallic layers of Co and CoFe sputtered onto the native oxide (SiO2) of Si substrates of different types. The switching can occur even without applying a bias field under discharging a capacitor through an FM/SiO2/Si sample via electric pads lying on its surface. The switching thresholds and biasing fields (if needed) are found to be much lower in samples based on low-resistivity (∼10 mΩ cm) substrates. It is argued that the discharge induces localized breakdown of the SiO2 layer, and so, the discharge current is able to flow through the Si substrate. This current produces the magnetic (Oersted) field inside the FM layer, which is sufficient for the switching. Such on-chip pulsed magnetic fields generated in FM/SiO2/Si structures can be employed instead of bulky electromagnets for developing magnetic technologies, which would be compatible with Si-based electronics.