Materials Research Science and Engineering Center


Date of this Version



Published in IEEE TRANSACTIONS ON MAGNETICS, VOL. 43, NO. 6, JUNE 2007. Copyright © 2007 IEEE. Used by permission.


The effect of surface anisotropy on the magnetization reversal in small magnetic particles is investigated. The model considers particles of cubic shape cut from a tetragonal crystal with cube faces in the (001) and equivalent planes. In particles having diameters of less than about 10 nm, the coercivity approaches the Stoner–Wohlfarth limit, but the anisotropy field differs from that of the bulk of the particles. With increasing particle size, the nucleation modes acquire the character of magnetic surface or bulk modes that reduce the coercivity.