Ferroelectric response of Na0.9Li0.1NbO3 at room temperature

Polycrystalline samples of the dielectric, ferroelectric Na0.9Li0.1NbO3 were synthesized by means of solid-state reaction using different ramps of temperature. High purity precursors Nb2O5, Na2CO3 and Li2CO3 were stoichiometricaly mixed and heated at 1373 K for 6 hours in air atmosphere. The Na0.9Li0.1NbO3 samples were characterized by means of diffraction of X-rays using a Panalytical X'Pert Pro diffractometer. The obtained diffractograms were refined by Rietveld procedure using the software Maud. The results show that Na0.9Li0.1NbO3 crystallizes in an orthorhombic structure (space group Pbma). The refined diffraction patterns also suggest a possible replacement of the Na ions by Li ions in the parent, ferroelectric NaNbO3 compound. For electrical characterization of the samples, electrical polarization curves were measured using a Radiant Technologies RT66A test system for ferroelectric materials. The polarization versus applied electrical dependence shows a hysteretic behavior verifying the ferroelectric character of the material. A maxima polarization of 130 tC/m2 is obtained at room temperature.