Effect of layer number on ferromagnetic properties in aurivillius Bi4Bin-3Fen-3.2Co0.2Ti3O3n+3 ceramics

Abstract Aurivillius Bi 4 Bi n -3 Fe n -3.2 Co 0.2 Ti 3 O 3 n +3 (BFCT, n =4–7) ceramics were prepared by the hot-press method. X-ray diffraction and high-resolution transmission electron microscopy analysis indicate a successful synthesis of pure phase BFCT samples. All samples show significant magnetic moments at the room temperature. Interestingly, the remanent magnetization (2 Mr ) increases with the increase of n , which was found to be 21.53 emu/mol, 413.49 emu/mol, 472.78 emu/mol and 727.03 emu/mol for n =4, 5, 6 and 7 ceramics, respectively. This phenomenon can be ascribed to the increased coupling probability of Fe-O-Co with increasing n . Besides, the odd-layered compounds are likely to be beneficial for enhancing the 2 Mr , due to that their crystalline structures may endure larger distortions when compared with the even-layered compounds.