Exact calculation of demagnetization field in micromagnetic simulation of shielded read heads

In micromagnetic simulation of shielded GMR heads, the self-demagnetizing f ield is usually calculated under the assumption that the two shields extend to infinity beyond the air bearing surface. Under this assumption, the dem agnetization tensor for rectangular cells in free space and the method of i mages are used to calculate the self-demagnetizing field in the sensor. An unanswered question for this approach is how accurate it is. In this work, the Fourier series method is used to calculate the self-demagnetizing field of the sensor in the shielded environment exactly. Simulation results from this rigorous approach and the common approach are compared for both simpl e spin valve and synthetic antiferromagnet (SAF) biased spin valve heads. I t is shown that the error of the common approach is very small for a SAF sp in valve head and can be as large as 10% for a simple spin valve head. (C) 2001 American Institute of Physics.