Compositional Tuning of the Aurivillius Phase Material Bi₅Ti_3-2xO₁₅(0 ≤ ≤ 0.4) Grown by Chemical Solution Deposition and its Influence on the Structural, Magnetic, and Optical Properties of the Material

A series of Aurivillius phase materials, Bi5Ti NbxO15 =0.1, 0.2, 0.3, and 0.4), was fabricated by chemical solution deposition. The effects of aliovalent substitution for the successful inclusion of Fe by replacing Ti {{4}+} were explored as a potential mechanism for increasing magnetic ion content within the material. The structural, optical, piezoelectric, and magnetic properties of the materials were investigated. It was found that a limit of {x} = {0.1} was achieved before the appearance of secondary phases as determined by the X-ray diffraction. Absorption in the visible region increased with increasing values of {x} corresponding to the transition from the valence band to the conduction band of the Fe- {e} energy level. Piezoresponse force microscopy measurements demonstrated that the lateral piezoelectric response increased with increasing values of {x}. Magnetic measurements of Bi5Ti2.8Fe1.1Nb0.1O15 exhibited a weak ferromagnetic response at 2, 150, and 300 K of 2.2, 1.6, and 1.5 eμcm3 with {H}{c} of 40 , 36, and 34 Oe, respectively. The remanent magnetization {M}{R} of this sample was found to be higher than the range of reported values for the Bi5Ti3Fe1O15 parent phase. Elemental analysis of this sample by energy-dispersive X-ray analysis did not provide any evidence for the presence of iron-rich secondary phases. However, it is noted that a series of measurements at varying sample volumes and instrument resolutions is still required in order to put a defined confidence level on the Bi5Ti2.8Fe1.1Nb0.1O15 material being a single-phase multiferroic.