Preparation and Dielectric Properties of Bi1.5MNb1.5O7 (M = Cu, Mg, Mn, Ni, Zn) Pyrochlore Oxides

Bi_1.5MNb_1.5O₇ (M = Cu, Mg, Mn, Ni, Zn) oxides are prepared by solid-state reactions and are shown, by x-ray diffraction, to have cubic pyrochlore structure with lattice parameters in the range a= 10.495–10.570 Å. The phases with M = Cu, Mg, Mn, and Ni are prepared and characterized for the first time. The 1- and 10-kHz dielectric permittivity and loss tangent of Bi_1.5MNb_1.5O₇ are measured from 80 to 300 K. For M = Mg, Ni, and Zn, exhibits a maximum at 130, 150, and 90 K, respectively.