Structure and dielectric properties of Sm3+ modified Bi4Ti3O12- SrBi4Ti4O15 intergrowth ferroelectrics

Abstract

Novel samarium modified intergrowth ferroelectric ceramics, namely Bi 4 Ti 3 O 12 -SrBi 4 Ti 4 O 15 , were synthesized by conventional solid state reaction method and sintered at 1100°C for 5 h. X-ray diffraction studies revealed the formation of a single phase with the signature of intergrowth oxide and plate like morphology was observed by scanning electron microscopic analyses. The orthorhombicity, the grain size and transition temperature were found to decrease with the increase of Sm content. The dielectric and modulus measurements were performed at different temperatures and frequency ranges. The transition temperature was found to be around 500°C. The variations of imaginary part of modulus and dielectric constant with the temperature showed diffuse phase transition. The results are corroborated to the defect based mechanism and Curie deviation factor was evaluated by using the modified Curie-Weiss law. Polarization-electric filed curves displayed a typical narrow hysteresis loop at room temperature by applying an electric field of 70 kV/cm. However, above room temperature the hysteresis loop area was found to be increased. The overall results revealed that the complex dipoles and oxygen vacancies are playing a dominant role in the dielectric and electrical properties, and therefore the adopted intergrowth processing was found to be an effective approach to obtain potentially good ferroelectric materials.

Magnetic and Magnetoelectric Properties of AurivilliusThree- and Four-Layered Intergrowth Ceramics

“…Finally, all the ordering of these materials tunes to multiferroic applications. The unsaturated and nonsymmetric nature of loops is associated with the leaky nature, on account of the high concentration of oxygen vacancies [7,17]. It is also observed that the coercive field and polarization increase with the applied voltages, as shown in Figure 5a-c.…”

“…The intergrowth of the BLSFEM compound consists of one unit cell of one-half the unit cell of m-layered and the other half unit cell of (m + 1) layered compounds along the c-axis [6,17]. Earlier we reported the electrical properties of intergrowth of Sm-modified Bi 4 Ti 3 O 12 and SrBi 4 Ti4O 15 [17]. The XRD pattern of intergrowth is well indexed with the SrBi 8 Ti 7 O 27 (eight layers) compound.…”

Review on energy storage in lead‐free ferroelectric films

“…Here in this perovskite layers A = Bi 3+ and B = Fe 3+ , Ti 4+ and n in (A n − 1 B n O 3 n + 1 ) 2− refers to the number of perovskite‐like packets between the Bi 2 O 2 layers 77‐79 . A combination of 1 mol of a three‐layered monoclinic Bi 4 Ti 3 O 12 and m moles of rhombohedral perovskite BiFeO 3 , with m = 1, 2, and 5, are considered as four‐, five‐, and eight‐layered compounds: Bi 5 FeTi 3 O 15 , Bi 6 Fe 2 Ti 3 O 18 , and Bi 9 Fe 5 Ti 3 O 27 and these are simultaneously ferroelectric and AFE in nature 80 . Due to coexistence of ferroelectric and magnetic ordering these are candidate materials for magnetoelectric applications.…”

“…[77][78][79] A combination of 1 mol of a three-layered monoclinic Bi 4 Ti 3 O 12 and m moles of rhombohedral perovskite BiFeO 3 , with m = 1, 2, and 5, are considered as four-, five-, and eight-layered compounds: Bi 5 FeTi 3 O 15 , Bi 6 Fe 2 Ti 3 O 18 , and Bi 9 Fe 5 Ti 3 O 27 and these are simultaneously ferroelectric and AFE in nature. 80 Due to coexistence of ferroelectric and magnetic ordering these are candidate materials for magnetoelectric applications. Lead-free and fatigue free ferroelectric aurivillius oxides with unmatched fatigue resistance are attributed to their unique crystalline structure with perovskite-like slabs with inter growth of (Bi 2 O 2 ) 2+ layers act as barriers to inhibit the long-range diffusion of space charges and defects, which are generated during the domain wall motion and form the electrode-ferroelectric interface.…”