论文信息 - Dielectric properties and structure of Bi4NbO8Cl and Bi4TaO8Cl

Dielectric properties and structure of Bi4NbO8Cl and Bi4TaO8Cl

The layered intergrowth phases Bi4MO8Cl (M = Nb, Ta), structurally related to the well-known Aurivillius phase ferroelectrics, have been studied using SHG and a.c. impedance techniques. Both undergo a polar to centrosymmetric phase ferroelectric-type transition (Tc = 765 and 640 K for M = Nb and Ta, respectively). The crystal structure of the low temperature phase of Bi4NbO8Cl has been re-analysed, and a tentative structure for Bi4TaO8Cl determined, from powder neutron diffraction data. The basic structural features are confirmed, but significant details differ from the previously reported X-ray structure of Bi4NbO8Cl.

[1] M. C. Scott,et al. Fatigue-free ferroelectric capacitors with platinum electrodes , 1995, Nature.

[2] J. Mercurio,et al. The crystal chemistry and dielectric properties of the Aurivillius family of complex bismuth oxides with perovskite-like layered structures , 1992 .

[3] K. Knight. The crystal structure of russellite; a re-determination using neutron powder diffraction of synthetic Bi2WO6 , 1992, Mineralogical Magazine.

[4] S. K. Kurtz,et al. A powder technique for the evaluation of nonlinear optical materials , 1968 .

[5] L. N. Kholodkovskaya,et al. The crystal chemistry of layer metal oxide halides and oxide chalcogenides (Sillèn phases) , 1992 .