Effects of bismuth/lanthanum-substitution on optical, dielectric and magnetic properties of bismuth-iron titanate

Author(s)

Dias, Jeferson Almeida ; Gualdi, Alexandre Jose ; Dalla Costa, Leonardo Jose ; Bretas, Rosario Elida Suman ; Rodrigues, Ana Candida Martins ; Morelli, Marcio Raymundo

• Document type: Journal article
• Source: MATERIALS TODAY COMMUNICATIONS; v. 24, p. 9-pg., 2020-09-01.

Abstract

In this paper, the structural changes and optical, dielectric and magnetic properties of Bi5Ti3FeO15-based compounds were investigated following the gradual replacement of bismuth by lanthanum. The powders were produced by a solid-state reaction method; the LaxBi5-xTi3FeO15 system with x varying from zero up to 2.5 was investigated. The phase formation, structure and particle morphology were evaluated for these materials, as well as the optical, dielectric and magnetic properties. The results revealed that lanthanum cations can be totally solubilized in the LaxBi5-xTi3FeO15 system up to x equals 1.5. Secondary phases begin to appear beyond this value. The study of optical properties revealed that the powders partially absorb the visible spectrum. The presence of iron cations reduced the bang gap energy of bismuth titanates, whereas Bi3+/La3+ substitution increased this parameter. The presence of lanthanum increased the electrical resistivity of the materials at room and higher temperatures up to the lanthanum-saturation limit. Simultaneously, the dielectric permittivity at low frequencies also increased. The investigation of magnetic properties demonstrated less defined tendencies depending on lanthanum content. However, the coercivity was gradually reduced by the presence of lanthanum in the materials structure, while the saturation magnetization enhanced for high lanthanum content. Therefore, this work presents promising properties of the LaxBi5-xTi3FeO15 system for several magneto-optoelectronic uses, and is also a guide to produce optimized materials and devices for these applications. (AU)

• FAPESP's process: 15/23329-3 - Development of polymeric nanocomposites for different applications in energy
• Grantee: Rosario Elida Suman Bretas
• Support Opportunities: Regular Research Grants