Dielectric properties of the ferroelectric Bi₂Ti₃O₉ceramics

Dielectric permittivity and electric modulus in Bi2Ti4O11

“…3͑b͒, one can see that at frequencies higher than 5.1ϫ10 4 Hz, ⑀Љ increases monotonically from Ϫ150 to 150°C, then a bump appears at around 200°C which shifts to lower temperature as the frequency decreases. This becomes a distinct peak below 4.5ϫ10 3 Hz, whose position continues to move to lower temperatures at lower frequencies. We attribute this behavior to a low frequency dielectric relaxation.…”

“…A strong low-frequency dielectric dispersion was observed in Bi 2 Ti 2 O 7 ͑Ref. 1͒ and Bi 2 Ti 3 O 9 , 3 while Bi 4 Ti 3 O 12 has several dielectric relaxation peaks below 950°C. 7 It is generally accepted that the presence of oxygen vacancies in the compounds of the system (Bi 2 O 3 ) m -(TiO 2 ) n plays an important role to the dielectric properties of the polycrystalline ceramics.…”

“…1 A diffuse ferroelectric phase transition was observed in Bi 2 Ti 3 O 9 (mϭ1,nϭ3) in the temperature range 200-280°C. 3 However, Bi 2 Ti 4 O 11 (mϭ1,nϭ4) was determined to be an antiferroelectric. Subbarao first studied the temperature dependence of the dielectric constants in Bi 2 Ti 4 O 11 at a fixed frequency (10 5 Hz) and found a phase transition at 250°C.…”

Dielectric properties of the ferroelectric ceramics

“…A nonferroelectric phase transition in B2T4 at temperature T ≈ 250 • C was observed by Subbarao [10].This phase transition was defined more accurately by Meng et al [18] as ferroelastic, whereas no phase transition was observed by Speranskaya. The phase transition in B2T3 was determined to be ferroelectric [19][20][21].…”