Structural and magnetic properties of Ca-substituted barium W-type hexagonal hexaferrites

A series of W-type hexagonal ferrites with the composition Ba1-xCaxCo2Fe16O27 (x=0, 0.1, 0.3, 0.4 and 0.5) were synthesized using a sal gel method. The effects of doping on structural and magnetic properties are studied by X-ray diffraction, thermal analyzer, scanning electron microscopy, vibrating sample magnetometer and vector network analyzer, respectively. The X-ray diffraction analysis shows that the samples belong to the W-type hexagonal ferrite. The lattice constants a and c decreases as Ca contents increases. The grains exhibit well defined hexagonal shape. The saturation magnetization and the intrinsic coercive force increases with the increase of he Ca substitution amount. The real parr of complex permittivity (epsilon') and imaginary parr (epsilon '') increase with more addition of Ca2+ amount. The imaginary parr of complex permittivity (mu') increases and the real parr (mu '') goes down afrer Ca2+ is doped. Furthermore, the Ca2+ ions doped in he ferrire improved microwave absorbency. (C) 2014 Published by Elsevier B.V.