Design of CF-SPT Head Having Large Recording Field and Small Stray Field using 3-D ON/OFF Method

In this research, a practical 3-D topology optimization technique combined with the edge-based finite element method is examined. The optimization of cusp field (CF) SPT head having magnetic shield is performed by using the topology optimization technique, so that the leakage flux in the adjacent bit and adjacent track can be reduced. It is shown that the obtained optimal topology is affected by the choice of target region. The 3-D optimization of SPT head is carried out using the edge-based FEM and a topology optimization method. A topology optimization algorithm (ON/OFF method) considering the existence of material (ON/OFF) in each element is adopted. The adjoint variable method taking account of the nonlinear magnetic property is applied as a sensitivity analysis method.