Synthesis and dielectric enhancement of rare-earth ions substituted lanthanum tantalate solid solutions

Rare earth ions (Re3+: Eu3+, Sm3+, Er3+, Dy3+) substituted solid solutions withchemicalcomposition Li(1 + x)(1-z)RezTa1-xTixO3 (x = 0.11, z = 0.025) using solid state method, with final sintering at 1150 degrees C for 10 h. Structural analysis of the prepared solid solutions was performed using X-ray Diffraction (XRD), Fourier Transform-Infra Red (FT-IR), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Transmission Electron Microscope (TEM). XRD analysis confirmed the presence of hexagonal geometry in the synthesized solutions. Spherical shaped grains were demonstrated in the SEM micrographs, with relative density > 97%. Average particle size, obtained from the TEM images, varied in 196-272 nm range. Tauc plots show that the prepared rare earth ions doped solid solutions observe optical band gap (E-g) in 3.77-3.93 eV range. Photo-luminescence (PL) spectrum of Eu-doped LTT solid solutions exhibits a strong emission peak of red colour at emission wavelength of 624 nm. Dielectric properties of the prepared solutions showed enhancement with doping of different rare earth ions (Eu3+, Sm3+, Er3+, Dy3+). Out of all the prepared solid solutions, the highest dielectric constant was registered by erbium doped solution. As a result of doping of rare earth ions, improvement was observed in reflective properties of these samples, using open-circuit approach in X-band (8.2-12.4 GHz) frequency range. Therefore, the prepared solid solutions can be potential candidates for applications in electro-optics devices and microwave reflectors.