Preparation and high resolution structural studies of LixAg1-xNbO3lead free piezoelectrics

Publication date: Available online 13 October 2018Source: Journal of Solid State ChemistryAuthor(s): Umair Farid, Hidayat Ullah Khan, Maxim Avdeev, Thomas A. Whittle, Brendan J. KennedyAbstractSolid solutions of the type (LixAg1-x)NbO3 with x = 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09 and 0.10 have been synthesized by a mixed oxide route. The samples were characterized by synchrotron X-ray diffraction (S-XRD), neutron powder diffraction (NPD) and Raman spectroscopy. Rietveld refinements against both the S-XRD and NPD data shows that pure AgNbO3 crystalizes in orthorhombic, Pmc21 space group with a unit cell 2 ap×2 ap× 4ap (where ap is the fundamental perovskite lattice parameter). The sample with x = 0.10 has rhombohedral R3c symmetry with a 2ap×2ap×12ap unit cell. The composition induced orthorhombic to rhombohedral phase transition starts at x ~ 0.05 and is complete by x ~ 0.07. Both phases are present in the region 0.05 ≤ x ≤ 0.07. The Raman spectra were consistent with the S-XRD and NPD data thereby confirming the onset of the structural phase transition in the region 0.05 ≤ x ≤ 0.07. Temperature dependent S-XRD measurements of AgNbO3 revealed the phase transition sequence to be Pmc21↔~340kPbcm↔~630Cmcm↔~650KP4/mbm↔~880Pm3̅m.Graphical abstractThe influence of Li doping on the crystal structure of oxides of the type (LixAg1-x)NbO3 is established using a combination of synchrotron X-ray diffraction, neutron powder diffraction and Raman...

Source: Journal of Solid State Chemistry - October 13, 2018 Category: Chemistry Source Type: research