Abstract
LixAg1-x(Nb0.5Ta0.5)O-3 (0 <= x <= 0.25) solid solutions have been fabricated by the mixed oxide method. Compositions with x <= 0.15 were single phase perovskite by x-ray diffraction (XRD) and could be indexed using the end member, Ag(Nb0.5Ta0.5)O-3 Pbcm cell, root 2a, root 2a, 4a (where a is the pseudocubic lattice parameter). For x >= 0.20, Li(Nb, Ta)O-3 peaks emerged as a second phase. Electron diffraction patterns from the perovskite phase could also be indexed according to the Pbcm cell but there was a systematic decrease in the intensity of {00 1/4}(p) as Li concentration increased which indicated that the correlation length of cation displacements perpendicular to c decreased from long to short range order. The reduction in correlation length of cation displacements resulted in a convergence of the M-1-M-2-M-3 transitions to give a single broad, frequency dependent maximum at x=0.15. Further increase in Li concentration did not qualitatively affect the temperature dependent dielectric data, consistent with the solubility limit determined by XRD. P-E loops did not show any significant enhancement in switchable polarization in the system with the majority of samples exhibiting a linear dielectric response. (C) 2010 American Institute of Physics. [doi:10.1063/1.3485813]