Magnetoelectric Coupling Effects in Tb-Doped BiFeO3 Nanoparticles

The magnetic, electric, and optical properties in Tb-doped BiFeO3 nanoparticles as functions of size and doping concentrations were investigated using a microscopic model, taking into account both linear and quadratic magnetoelectric (ME) coupling. We observed improved multiferroic properties and band-gap tuning. The magnetization and polarization increased with the decreased nanoparticle size and increased Tb-doping substitution x. The Neel temperature remained nearly unchanged whereas the Curie temperature was reduced with the increased x. There was doping-induced ME coupling. The dielectric constant is discussed as a function of the size, doping, and the magnetic field. The band gap decreased with the decreased size or increased Tb dopants due to competing effects of the compressive strain, oxygen defects on the surface, and Coulomb interactions. Increasing the Tb dopants and decreasing the nanoparticle size improved the ME effect.

Automated summary

The effects of size and doping concentrations on the magnetic, electric, and optical properties of Tb-doped BiFeO3 nanoparticles were investigated using a microscopic model that considers linear and quadratic magnetoelectric coupling. Improved multiferroic properties and band-gap tuning were observed. The magnetization and polarization increased with decreasing nanoparticle size and increasing Tb-doping substitution. The Neel temperature remained unchanged while the Curie temperature decreased with increasing Tb-doping concentration. Doping-induced magnetoelectric coupling was observed. The dielectric constant was discussed in relation to size, doping, and magnetic field. The band gap decreased with decreasing size or increasing Tb dopants due to competing effects of compressive strain, surface oxygen defects, and Coulomb interactions. Increasing Tb dopants and decreasing nanoparticle size improved the magnetoelectric effect.