Multiferroic Aurivillius-type Bi6Fe2-xMnxTi3O18 (0≤x≤1.5) ceramics with negative dielectric constant

Aurivillius-type ceramics Bi(6)Fe(2-x)Mn(x)Ti(3)O(18)x=0, 0.3, 0.9, 1.5 were obtained by a solid-state reaction method using high-purity TiO2, Bi2O3, Fe2O3 and Mn2O3 powders. The milled powder was calcined at 1113K for 4h. After calcination, the powder was milled again than pressed into pellets and sintered at 1213K for 4h. It was detected that the addition of manganese ions to the multiferroic five-layer Aurivillius-type structure affects the size of the grains. It was found that, the certain amount of manganese ions causes that the polarization of the material doped by them, have the direction opposite to the direction of the applied electric field. The doped material behaves like dia-electric material. The presented research complements the research concerning the Aurivillius ceramics doped with manganese. An attempt was made to explain the reasons for the negative values of dielectric constant and dielectric loss, that occur in manganese-doped five-layer Aurivillius type ceramics and which have not been described in the literature so far.