Enhancement of ferromagnetic and dielectric properties of lanthanum doped bismuth ferrite nanostructures

Cylindrical-shaped multiferroic Bi1−xLaxFeO3 (x = 0.0, 0.05, 0.1 and 0.15) were synthesized successfully by hydrothermal method. All samples were found to be rhombohedrally distorted perovskite structure. Diameter of the cylindrical particles reduces from ∼450 nm for x = 0.0 to ∼100 nm for x = 0.1 prepared under the same conditions. The Neél temperature as well as the dielectric constant was also found to increase with the increase in lanthanum content. Lanthanum doping also enhanced the magnetic properties. Magnetization measurements above room temperature show a significant increase in magnetization at around 400 °C. Enhanced magnetic properties due to lanthanum doping are caused by the breakage of spin cycloid as observed by electron spin resonance study.

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► Rod shaped lanthanum doped bismuth ferrite was obtained.
► The diameter of the particles were found to be decreasing on doping with lanthanum.
► Both ferromagnetic and dielectric properties enhanced.
► A transition due to spin canting is observed near 550 °C.
► Electron spin resonance study shows the breakage of spin cycloid due to doping.