  Two kinds of specimens, with the major phase of Sr3Co2Fe24O41 (Sr3Co2Z) and
SrCo2Fe16O27 (SrCo2W) hexaferrites respectively, were fabricated through
solid-state reaction. The phase composition, magnetic and dielectric
properties, magnetodielectric (MD) effect, magnetoelectric (ME) effect and
pyroelectric properties were studied. Results show that magnetic and dielectric
anomalies are induced by the magnetocrystalline anisotropy (MCA) transition.
They can be considered as characteristic properties (e.g., Sr3Co2Z at 370 K)
but are not a sufficient condition for the MD and ME coupling. The T-block
structure, existing in Sr3Co2Z but absent in SrCo2W, results in the dielectric
response with ferroelectric (FE) and magnetic contributions.
