Structural and magnetic properties of barium-gadolinium hexaferrites

A series of Gd-substituted M-type barium hexaferrites has been prepared by the ceramic route, according to the formula (Ba1-xGdx)O center dot 5.25Fe(2)O(3) (x= 0-0: 30). XRD analysis revealed that all the samples present primarily an M-type structure. Samples x=0 and x = 0: 05 are single-phase. Hematite (Fe2O3) and GdFeO3 were detected in the remaining samples. Coercivity (H-c) shows remarkably high values, similar to 293 kA/ m for x = 0.20 and 0.30 with a maximum of 322 kA/ m for x = 0.25. Specific saturation magnetization (sigma(sat)) of the samples presents a small increase up to x = 0.10. The microstructure examination indicates that Gd may act as a grain growth inhibitor. (C) 2006 Elsevier B. V. All rights reserved.