Structural study of K(x)Na(1 - x)NbO(3) (KNN) for compositions in the range x = 0.24-0.36.

Journal article

The structure of the A-site substituted perovskite K(x)Na(1 - x)NbO(3), x = 0.24-0.36, where a phase boundary was previously reported, has been determined by high-resolution X-ray powder and neutron powder diffraction studies. The structure of the x = 0.3 compound was refined in the monoclinic space group Pm at 293 K and in P4mm at 523 K. The Glazer tilt system of the room-temperature monoclinic phase is a(0)b(+)c(0), which has implications for the nature of the next symmetry change with composition towards pure potassium niobate. A phase-coexistence region at the transition between monoclinic and tetragonal phases was also identified, consistent with a first-order phase boundary. There is also evidence for an intermediate oxygen-octahedra tilted tetragonal phase.

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

• Publication status: Published
• Journal: Acta crystallographica. Section B, Structural science
• Volume: 65
• Issue: Pt 1
• Pages: 22-28
• Publication date: 2009-02-01
• DOI: 10.1107/s0108768108037361
• EISSN: 1600-5740
• ISSN: 0108-7681
• Language: English