Structures of K(0.05)Na(0.95)NbO3 (50-300 K) and K(0.30)Na(0.70)NbO3 (100-200 K).

Journal article

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: Zhang, N; Glazer, A; Baker, D; Thomas, P

• Publication status: Published
• Journal: Acta crystallographica. Section B, Structural science
• Volume: 65
• Issue: Pt 3
• Pages: 291-299
• Publication date: 2009-06-01
• DOI: 10.1107/s0108768109011057
• EISSN: 1600-5740
• ISSN: 0108-7681
• Language: English
• Keywords: Phase boundary; Piezoelectric material; Rietveld refinement; Neutron powder diffraction