The thermal stability range and magnetic properties of U-type hexaferrites

Single-phase polycrystalline U-hexaferrites with the composition Ba(4)A(2)Fe(36)O(60) (A = Co, Ni, Zn) were prepared by solid-state reaction synthesis employing high-energy milling or topotactic reaction and calcination at 1200 - 1300 degrees C. The Curie temperature and saturation magnetization of the samples were influenced by the composition, while the coercivity was more strongly influenced by the preparation conditions. (C) 2003 Elsevier B. V. All rights reserved.