Energy barrier and exchange coupling in spring-magnets

Summary form only given. The exchange-coupled nanocomposite magnets have potential for high energy products because materials with this configuration may take the advantages of high magnetization of the soft magnetic constituents and the high coercivity of the hard constituents. From the physical point of view, the energy-barrier, E/sub B/, the minimum energy required for magnetization reversal, is the key issue in controlling the magnetic properties. In this paper, a modeling analysis of exchange coupling between the soft and hard magnetic layers, and the energy-barrier E/sub B-S/, E/sub B-H/ is presented. We have derived the energy-barrier E/sub B-S/ and E/sub B-H/ as follows: E/sub B-S/=K/sub S/t/sub S/{1-[H-(J/M/sub S/t/sub S/)]/H/sub K-S/}/sup 2/ (H/sub K-S/=2K/sub S//M/sub S/; H\n\n\t\t