Domain nucleation in uniaxial ferromagnets

We use linearized micromagnetic theory to calculate the nucleation field and the form of the nucleation mode for finite-thickness platelets of uniaxial ferromagnets in arbitrarily oriented uniform external magnetic fields. To carry out this calculation, we use the results of the theory in the limit of very thick platelets, a generalization of the switching theory of Stoner and Wohlfarth. The nucleation field and mode for smaller specimens are then found as first-order deviations from the corresponding quantities of thick platelets. The nucleation mode has the form of incipient strip domains parallel to the field component in the platelet plane.