New La1−xTbxMnO3 nanoparticles: fabrication via wet chemical route for enhanced structural, electrical and dielectric parameters

Abstract

Rare earth Tb3+ doped LaMnO3 nanoparticles were fabricated via cheap facile wet chemical micro emulsion route. X-ray diffraction and spectral analysis by Fourier transform infrared radiation spectroscopy confirmed the formation of orthorhombic structure of La1−xTbxMnO3 nanoparticles. The crystallite size was found in the range 10–50 nm. The lattice parameters (a)–(c) and cell volume were decreased as the La3+ was replaced with Tb3+. This was attributed to the smaller ionic radius of Tb3+ (0.92 Å) as compared to that of La3+ (1.03 Å). Scanning electron microscopic images showed that the La1−xTbxMnO3 grains are well structured and have no cracks. They are non-homogeneous in size with occasionally aggregation. The dielectric measurements of La1−xTbxMnO3 nanoparticles performed in the frequency range 1 × 106 to 3 × 109 Hz showed that both Tb3+ contents and frequency decreased the dielectric parameters. At high frequency, the dipoles could not follow the alternating field and thus resulted in decreased dielectric parameters. The Tb3+ in LaMnO3 decreased the internal viscosity of the system that affected the dielectric parameters. DC-electrical resistivity was enhanced with the increased Tb3+ contents. This might be due to f–d orbital coupling between rare earth and transition metal cations in La1−xTbxMnO3 nanoparticles.