Domain wall movement in a rhombic Co thin film ring

• Rhombic Co rings were fabricated by e-beam lithography, with a 1.4 μm/0.7 μm major/minor diameter and 200 nm width.
• Magnetic Force microscope images show various magnetic remanent states of the rhombic ring due to an applied magnetic field.
• Magnetic switching was studied by anisotropic magnetoresistance measurements and calculations.

The magnetization switching of micron-scale thin film Co rhombic rings is studied by magnetic force microscopy and electrical measurements. The rhombic rings have a 1.4 μm/0.7 μm major/minor diameter with 200 nm width. A magnetic field ranged from 130 Oe to 200 Oe causes motion of domain walls (DWs) around the ring in a direction controlled by the magnetic field orientation. In addition to the well-known ‘onion’ and ‘vortex’ states, intermediate states such as horseshoe and hard-axis onion states were formed for certain field cycles, in agreement with micromagnetic simulations and anisotropic magnetoresistance calculations. DWs induce a 0.4% resistance change when the external magnetic field is cycled.

Co rhombic thin film ring and its magnetic states after applying a magnetic field.Figure optionsDownload as PowerPoint slide