Optical and dielectric characterization of gadolinium aluminate ceramic nanoparticles synthesized by combustion technique

Single phase nanocrystalline Gadolinium aluminate (GdAlO3) has been synthesized from Gadolinium oxide and Aluminium nitrate by auto-ignition citrate complex combustion process. The thermal decomposition of precursor and successive phase formation has been investigated using X-ray diffraction analysis (XRD), Thermo-Gravimetric Analysis and Differential Thermal Analysis (TGA/DTA) and Fourier Transform Infrared (FT-IR) spectroscopy analysis. X-ray diffraction analysis (XRD) revealed the formation of GdAlO3 with orthorhombic perovskite structure in the Pbnm space group. Transmission Electron Microscopy (TEM) has been employed for the particle-size analysis. The nanoparticle size is in the range of 30-50 nm. Surface morphology of the sintered pellet was obtained from High Resolution Scanning Electron Microscopy (HR-SEM). The absorption spectrum of the GdAlO3 nanoparticles shows characteristic cut edge which was attributed to direct allowed transitions through optical band gap of 3.15 eV. The dielectric measurements as a function of temperature have been carried out on the sample in the frequency range 1 Hz-1 MHz. Values of dielectric constant ε' and loss tangent tanδ were found to be temperature and frequency dependent. The dielectric constant and loss tangent at 100 KHz were ∼8.62 and ∼0.02 respectively.