Simplified Calculation of the Maximum Energy Product for the Hard/Soft/Hard Trilayers

Abstract

Energy products of the hard/soft/hard trilayer system with the directions of easy axes and applied field parallel to the plane have been calculated by a simplified method. The simplified calculation of the maximum energy product (BH) $_{\max }$ has been concluded, which indicates that (BH) $_{\max }$ for a given trilayer system can be calculated though solving the maximum value of energy product in the domain of the applied field. Energy products of systems with the infinite hard and the finite hard phases calculated by the simplified method have been compared with those calculated by the traditional method, which shows that the simplified method is applicable. The maximum energy product of trilayer system as a function of L h has been calculated systematically by the simplified method. The result shows that the energy product first increases then declines as the hard phase thickness increases, and an optimal hard thickness for a fixed soft thickness can be found. Consequently, the optimal proportion of composite phase can be obtained, which is significant to the experiment.