Dielectric and magnetic behavior of BaCd2-xSrxFe16O27 W-type hexagonal ferrites

Research highlights: → HEXAFERRITES are used as permanent magnet materials, but are also of great interest as magnetic recording media. → The possibility of the substitution of divalent is well known for the M-type, but no data are available for the W-type ferrites as Sr2+ with divalent substitution. → We examine the use of Sr2+ as divalent doping in preparation of barium based W-type ferrites. → The substitution of Cd2+ by Sr2+ enables to synthesize high coercive W-type hexaferrites suitable for magnetic recording and microwave absorber applications. - Abstract: We have prepared BaCd2-xSrxFe16O27 (x = 0, 0.5, 1, 1.5 and 2.0) W-type hexagonal ferrites by standard ceramic method. In this work, the structural, dielectric and magnetic properties have been studied of the prepared samples. The XRD analysis of the samples reveals single phase behavior sintered at 1400 oC for 6 h. The saturation magnetization (Ms) shows increasing behavior with the increasing concentration of Sr2+. While the coercivity (Hc) decreases rapidly up to 409 G for x = 1.5 and then increases for (x > 1.5) due to the preference of Cd2+ for tetrahedral sites and the number of spin-down magnetic ions. The real and imaginary parts of the dielectric constant (ε',ε'') and dielectric loss tangent (tan δ) are determined in the frequency range 0.1-107 Hz. It is observed that both the real and imaginary parts of the dielectric constant and tan δ decrease with the increasing concentration of Sr2+, which is due to the contribution of Cd2+ ions in addition to Fe3+ and Fe2+ ions to interfacial polarization.