Dielectric properties of Fe3+ doped Bi1.5ZnNb1.5O7 ceramics

The structure and dielectric properties of Bi
₂
O
₃
-ZnO-Nb
₂
O
₅
(BZN) pyrochlore ceramics doped with Fe
³⁺
were investigated. The crystal structure of (Bi
_1.5
Zn
_0.5
)(Zn
_0.5
Nb
_1.5-x
Fe
_x
)O
₇
(BZNF) ceramics is cubic pyrochlore structure (α-BZN) when x ≤ 0.1 mol and the second phase occurs at x = 0.135 mol. The lattice parameter increases with increasing Fe. When x ≤ 0.1 mol the dielectric constant decreases and the dielectric loss increases. All the compositions exhibit a typical relaxation behavior. The modified Curie-Weiss law is used to characterize the dielectric relaxation. With an increase in Fe concentration the Tm shifts towards lower temperature, the bond lengths of R
_A-O
and R
_B-O
slightly increase and the ξ fractional coordinate of O decreases until x = 0.135 mol, meanwhile the bond valence sum AV (O) decrease.