title: Structures of K(0.05)Na(0.95)NbO3 (50-300 K) and K(0.30)Na(0.70)NbO3 (100-200 K).
abstract: Rietveld refinement using neutron powder diffraction data is reported for the potential lead-free piezoelectric material K(x)Na(1-x)NbO3 (x = 0.05, x = 0.3) at low temperatures. The structures were determined to be of rhombohedral symmetry, space group R3c, with the tilt system a(-)a(-)a(-) for both compositions. It was found that some of the structural parameters differ significantly in the two structures, and particularly the NbO6 octahedral strains as a function of temperature. The 300 K profile for K(0.05)Na(0.95)NbO3 shows the coexistence of rhombohedral and monoclinic phases, which indicates that the phase boundary is close to room temperature; the phase boundary for K(0.30)Na(0.70)NbO3 is found to be at approximately 180 K.
authors.affiliation: Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, England. n.zhang1@physics.ox.ac.uk
authors.forename: N
authors.initials: N
authors.lastname: Zhang
authors.forename: A M
authors.initials: AM
authors.lastname: Glazer
authors.forename: D
authors.initials: D
authors.lastname: Baker
authors.forename: P A
authors.initials: PA
authors.lastname: Thomas