Two compounds Ba 6 Zn 0.67 Nb 9.33 O 3 and Ba 6 Zn 0.67 Ta 9.33 O 30 with tungsten bronze structure were synthesized in the BaO-ZnO-Nb 2 O 5 /Ta 2 O 5 systems by the conventional high temperature solid-state reaction....Two compounds Ba 6 Zn 0.67 Nb 9.33 O 3 and Ba 6 Zn 0.67 Ta 9.33 O 30 with tungsten bronze structure were synthesized in the BaO-ZnO-Nb 2 O 5 /Ta 2 O 5 systems by the conventional high temperature solid-state reaction.The stru cture and dielectric properties of Ba 6 Zn 0.67 Nb 9.33 O 3 and Ba 6 Zn 0.67 Ta 9.33 O 30 were determined by X-ray powder diffraction,scanning electron microscope a nd dielectric measurements.The results show that Ba 6 Zn 0.67 Ta 9.33 O 30 belongs to paraelectric phase of fully filled tetragonal tungsten bronze str ucture at room temperature with unit cell parameters a=1.26256(4)nm, c=0.39698(2)nm.The room temperature dielectric constant( ε )of Ba 6 Zn 0.67 Ta 9.33 O 30 ceramic reached108combined with a low dielectric loss of0.005at1MHz .While Ba 6 Zn 0.67 Nb 9.33 O 3 belongs to fully filled tetragonal tungsten bronze structure at room tempera ture with the unit cell parameters a=1.25940(3)nm,c=0.40008 (2)nm.Ba 6 Zn 0.67 Nb 9.33 O 30 ceramic shows significant relaxor behaviors,and the phase transition from f erroelectric to paraelectric occurred at55℃(at1MHz).The room temperature dielectric constant( ε )of ceramic reached570at1MHz.展开更多
A niobate was synthesized by doping Bi3＋ in the ternary system BaO- N O- Nb2O5. The crystal structure was determined by X- ray powder diffraction,and it belongs to tetragonal tungsten bronze structure at room tempera...A niobate was synthesized by doping Bi3＋ in the ternary system BaO- N O- Nb2O5. The crystal structure was determined by X- ray powder diffraction,and it belongs to tetragonal tungsten bronze structure at room temperature with unit cell parameters a=1.24777 (2) nm,c=0.39266(1) nm,α =β =γ =90° .Measurements of dielectric properties indicate that phase transitions of Ba3NaBiNb10O30 from paraelectric to ferroelectric occurs at 400℃ ,which is lower than that of B NaNb5O30.展开更多
文摘Two compounds Ba 6 Zn 0.67 Nb 9.33 O 3 and Ba 6 Zn 0.67 Ta 9.33 O 30 with tungsten bronze structure were synthesized in the BaO-ZnO-Nb 2 O 5 /Ta 2 O 5 systems by the conventional high temperature solid-state reaction.The stru cture and dielectric properties of Ba 6 Zn 0.67 Nb 9.33 O 3 and Ba 6 Zn 0.67 Ta 9.33 O 30 were determined by X-ray powder diffraction,scanning electron microscope a nd dielectric measurements.The results show that Ba 6 Zn 0.67 Ta 9.33 O 30 belongs to paraelectric phase of fully filled tetragonal tungsten bronze str ucture at room temperature with unit cell parameters a=1.26256(4)nm, c=0.39698(2)nm.The room temperature dielectric constant( ε )of Ba 6 Zn 0.67 Ta 9.33 O 30 ceramic reached108combined with a low dielectric loss of0.005at1MHz .While Ba 6 Zn 0.67 Nb 9.33 O 3 belongs to fully filled tetragonal tungsten bronze structure at room tempera ture with the unit cell parameters a=1.25940(3)nm,c=0.40008 (2)nm.Ba 6 Zn 0.67 Nb 9.33 O 30 ceramic shows significant relaxor behaviors,and the phase transition from f erroelectric to paraelectric occurred at55℃(at1MHz).The room temperature dielectric constant( ε )of ceramic reached570at1MHz.
文摘A niobate was synthesized by doping Bi3＋ in the ternary system BaO- N O- Nb2O5. The crystal structure was determined by X- ray powder diffraction,and it belongs to tetragonal tungsten bronze structure at room temperature with unit cell parameters a=1.24777 (2) nm,c=0.39266(1) nm,α =β =γ =90° .Measurements of dielectric properties indicate that phase transitions of Ba3NaBiNb10O30 from paraelectric to ferroelectric occurs at 400℃ ,which is lower than that of B NaNb5O30.
