Microeagnetic Calculation of the Nucleation Field in Nanostructured Two-phase Exchange-coupling α-Fe/Nd₂Fe₁₄B Multilayer Films

The thickness of soft and hard magnetic layer dependence curves of the nucleation field in nanostructured two - phase exchange-coupling a-Fe/Nd₂Fe₁₄B multilayer films was calculated by means of micomagnetic and variational methods. From our calctilation results the critical thickness of soft or hard layer was found. At this critical thickness of which the sizes are nearly to the width of the domain wall the nucleation field H_N reaches its maximum（ H_N=4.5~5.5T）. Beyond this critical thickness the nucleation field fall off rapidly. This result is in agreement with the Rave et al. theoretical results by means of finite-element method. Having taken account of the influence of the phase constitute, the inhomogeneity of two phase crystal particle size and procession parameters, our result are also agree with Shindo et al. experimental results by radio frequency（RF） sputtering and theoretical estimate results. This shows that the present physical model and computational methods used are effective and successful.