Shape Magnetic Anisotropy Field in Permalloy Ellipses for Sensor Applications

Controlling magnetic anisotropy is essential for obtaining the desired magnetic properties in functional spintronic devices. In patterned structures, the shape of the magnetic units and the fabrication conditions significantly influence magnetic switching behavior and the occurrence of ferromagnetic resonance. This study investigates the magnetic anisotropies in Permalloy (Ni₇₉Fe₂₁) ellipses using ferromagnetic resonance measurements and theoretical analysis. The shift in the ferromagnetic resonance peak is directly linked to variations in the effective magnetic fields within the patterned ellipses.