Every software package contains a full set of examples suitable for that version and are installed with the software. If you see examples here that are not in your installation you should consider updating to a later version of the software. These examples can be used by beginners and advanced users for product evaluation, teaching purposes, and self-training.
Required Modules
Victory Mesh
- 3D Meshing
- 3D Solid Modeling
Victory Device
- 3D Simulator
- 3D MRAM
In this example, the magnetic switching of an SOT MRAM devices is achieved by the use of an external magnetic field. The input deck includes:
-) The structure generation of the SOT MRAM device using Victory Mesh.
-) The micromagnetic simulation of the switching process using Victory Device.
In Victory Mesh, the heavy metal layer and the SOT pillar structure are generated separately by using the CUBOID and the LAYERS statement, respectively, and are then combined to one complex on the subsequent JOIN statement. Afterwards, the REMESH command is applied to create a Delaunay mesh on this complex, and the region as well as the interface refinement schemes are used to prepare the structure for the subsequent device simulation.
Victory Device must be called with the simulation flag “-mram ” for micromagnetic simulations. First, the device structure is loaded with the flags ENABLE.SOT, ENABLE.SOT.BCS, and ENABLE.INT.SOC set on the MESH statement. The electrodes and the SOT interface are geometrically defined and enumerated on the ELECTRODE and the INTERFACE statements, respectively. Then, the region and interface parameters of the Landau-Lifshitz-Gilbert equation as well as the Spin-Drift-Diffusion equation are specified on the LLGE and SDDE statements, respectively. It is stressed that the vector of the external magnetic field is given on the LLGE statement using the parameter EXTERNAL.FIELD.
The SOT command is applied to define the parameters for the Spin-Hall effect and the SOT interface models. The parameter SPIN.HALL.LAYER identifies the heavy metal layer and the parameter SPIN.HALL.ANGLE is used the additional SHE term in the Spin-Drift-Diffusion equation. The spin mixing parameters (SPIN.MIXING.CONDUCTANCE.REAL, SPIN.MIXING.CONDUCTANCE.IMAG) define the spin scattering at the SOT interface according to the magnetoelectronic circuit model. The Rashba Edelstein effect is specified by the potentials SPIN.DEPENDENT.POTENTIAL, EXCHANGE.POTENTIAL, and RASHBA.POTENTIAL along with the parameters FERMI.WAVE.VECTOR, RELAXATION.TIME.NM, and the RELAXATION.TIME.FM.
The initial anti-parallel magnetic configuration is specified on the LOAD statement.
The logged quantities and their saved distributions are selected on the PROBE and the OUTPUT statements, respectively.
The following SOLVE statement defines a transient simulation up to 10ns, where a fixed bias is applied for the contacts on the heavy metal layer and a floating bias for the contact on the SOT pillar.
The spin separation due to the SHE is visible in the y- and the z-component of the spin accumulation. The spin accumulation along with the external magnetic field results in a complete switching of the magnetization as visible in the time evolution of the free-layer magnetization and the two snapshots of the magnetization in the z-direction.
Images
