Layer Effects on the Magnetic Behaviors of Aurivillius Compounds Bin+1Fen-3Ti3O3n+1 (n=6, 7, 8, 9)

Bin+1Fen-3Ti3O3n+1 (BFT-n, n = 6, 7, 8, 9) ceramics were prepared using Pechini's method and their magnetic behaviors were investigated. XRD and HRTEM results suggested that BFT-n have the pure Aurivillius structure. Magnetic properties of BFT-n depend largely on their layer numbers. BFT-6 exhibits a paramagnetic (PM)-like characteristics with a small portion of weak antiferromagnetic (AFM) property; while spin glass (SG)-like characteristics was observed for the BFT-n (n 7) samples. An amazing exchange bias phenomenon was observed in BFT-n (n 7) ceramics, of which shifts in both vertical and horizontal direction were found in the magnetic hysteresis loops as the functions of testing temperature and the layer number (n). For BFT-8, the maximum H-E is 3911 Oe when measured at 5 K. The AFM/SG interface should be the origin for the observed exchange bias effect, which was aggravated with the increased layer numbers for the enhanced coupling probability among Fe3+ ions. The fantastic exchange bias behavior of BFT-n (n 7) makes them a good single-phase candidate for future spintronic devices.