Inhomogeneous structure and magnetic properties of aurivillius ceramics Bi₄Bi_n-3Ti₃Fe_n-3O_3n+3

Structures of Aurivillius ceramics Bi₄Bi_n-3Ti ₃Fe_n-3O_3n+3 with n = 3-9 have been investigated by X-ray powder diffraction and high-resolution transmission electron microscopy. The Aurivillius ceramics Bi₄Bi_n-3Ti ₃Fe_n-3O_3n+3 with n = 3-5 exhibit homogeneous layered structure. However, the ceramic samples with n = 6-9 are composed of mixed Aurivillius phases with different layer numbers, in which the stacking faults of the disordered intergrowth of different n-layered perovskite blocks and the so-called "side-stepping" of the (Bi₂O ₂)²⁺ layers are generally observed. Magnetic measurements indicate that Fe cations couple antiferromagnetically and the inhomogeneity of composition exists in the samples. The magnetic properties are obviously influenced by the inhomogeneous structure and composition.