Exchange Coupling and Energy Product in Random Two- Phase Aligned Magnets

Authors

Ralph Skomski, University of Nebraska-LincolnFollow
J.M.D. Coey, Trinity College, Dublin, Ireland

Date of this Version

March 1994

Comments

Published by IEEE TRANSACTIONS ON MAGNETICS, VOL. 30, NO. 2, MARCH 1994.

Abstract

Size effects in two-phase Boolean magnets composed of an aligned hard phase and a soft phase with high magnetization are investigated. In 'over-critical' magnets, where the size of the soft regions is larger than the Blochwall width δ_h of the hard phase, the energy product is reduced compared to the corresponding 'undercritical' magnets with small soft regions, where theoretical energy products as high as 1 M J / m³ have been predicted. Nevertheless, the theoretical energy product only gradually drops with increasing size of the soft regions, and it may still exceed the theoretical energy product 516 kJ/m³ of Nd₂Fe₁₄B.