  Conjugate gradient methods for energy minimization in micromagnetics are
compared. When the step length in the line search is controlled, conjugate
gradient techniques are a fast and reliable way to compute the hysteresis
properties of permanent magnets. The method is applied to investigate
demagnetizing effects in NdFe12 based permanent magnets. The reduction of the
coercive field by demagnetizing effects is 1.4 T at 450 K.
