Voltage control of magnetic domain wall injection in strain-mediated multiferroic heterostructures
Effective control of the domain wall (DW) injection in the magnetic nanowires is of great importance for future novel device applications in spintronics, and currently rely on magnetization switching by the local external magnetic field obtained from metal contact lines or spin-transfer torque (STT) effect from spin-polarized current. However, the external field is an obstacle for realizing practical spintronic devices with all-electric operation, and high current density can occasionally damage the devices. In this work, voltage controlled in-plane magnetic DW injection into a magnetic nanowire in the strain-mediated multiferroic heterostructures is studied by means of fully coupled micromagnetic-mechanical Finite Element Method (FEM) simulations. We propose a engineered shaped nano-magnetic on piezoelectric thin film that a 180° magnetization rotation in the DW injection region accomplished with in-plane piezostrain and magnetic shape anisotropy, thereby, leading to a DW injection into the nanowire. In this architecture, we computationally demonstrate a repeated creation of DWs by voltage-induced strains without using any magnetic fields. Our FEM simulation results demonstrated an ultralow area energy consumption per injection (~52.48 mJ/m^2 ), which drastically lower than the traditional magnetic field and STT driven magnetization switching. A fast-overall injection time within ~3.4 ns under a continuous injection is also demonstrated. Further reduction of energy consumption and injection time can be achieved by optimization of the structure and material selections. The present design and computational analyses can provide an additional efficiency method to realize low-power and high-speed spintronics and magnonic devices.