Size and shape effects of patterned polycrystalline islands

Patterned polycrystalline cobalt islands with different sizes and shapes have been simulated by a micromagnetic simulator. An elliptic shape is found to be preferred for patterned islands to form a uniform single domain demagnetised state and have sharper squareness compared with square islands. Therefore, in a single-bit-per-island recording system, the elliptic islands could lead to a stable state and a predictable overwrite process and act independently even in a closely packed arrays.