Doping effect on the dielectric property in bismuth titanate

Abstract

The dielectric property complemented by the mechanical measurement (internal friction) in the doped Bi4Ti3O12 [Bi4−xLaxTi3O12 (x=0.5,0.75,1) and Bi4−y/3Ti3−yNbyO12 (y=0.015,0.03,0.06)] was systematically investigated from room temperature to 350 °C. In the plot of dielectric loss versus temperature for Bi4Ti3O12 (BiT), a relaxation peak was confirmed to be associated with the motion of the oxygen vacancy. It is found that the La doping at site A is in favor of improvement of the fatigue property, in contrast, the Nb doping at site B can mainly enhance the remanent polarization. Appropriate La doping at site A of perovskite-type unit in BiT enhances the chemical stability of oxygen vacancy by improving the height of the potential barrier for hopping and enhances the mobility of domain by the changing of domain structures. While the Nb doping at site B could induce the distortion of oxygen octahedral and reduce the oxygen vacancy concentration by a compensating effect so that it results in an enhancement of remanent polarization.

Improved electrical properties in La- and V-co-doped Na0.5Bi4.5Ti4O15 thin films

“…The defects can be suppressed by substituting lanthanide ions for A-site ions or the substitution of donor ions for B-site ions in BLSFs. The doping of lanthanide ions for Bi-site enhances the chemical stability of oxygen vacancies and increases the activation energy of oxygen vacancies, leading to increase of breakdown field [25]. The doping of donor ions for Ti-site suppresses the oxygen vacancies accompanied with bismuth vacancies due to the charge neutrality [7,10].…”

Enhanced dielectric properties of bismuth titanate/silver composites

“…(see refs. [9,10], and literature cited therein). It is reported that the presence of large amounts of metallic phase in ferroelectric matrix can result in a significant improvement of the dielectric and ferroelectric properties [11,12].…”

Structure dependence of the ferroelectric properties of Bi3.25Ln0.75Ti3O12 (Ln=La, Nd, Sm, Dy) ceramics

“…Bi 4 Ti 3 O 12 (BIT) is one of the more extensively studied materials among the BLSF family due to its large spontaneous polarization along the a-axis (approximately 50 μC/cm 2 ), [4] low processing temperature, high Curie temperature, and lead-free composition. However, it is well known that oxygen-vacancy migration in BIT produces significant degradation problems associated with the ferroelectric properties such as high leakage current and small remnant polarization (2P r ∼ 15 μC/cm 2 ) [5,6]. Recently, it has been reported that the oxygen-vacancy migration in BIT ceramics with the substitution of rare-earth ions has a significant effect on its electric properties.…”

“…BLSF ceramics have the general formula of (Bi 2 O 2 ) 2+ (A m−1 B m O 3m+1 ) 2− , where A=Bi, Pb, Ba, Sr, La, Ca, Na, K; B=Ti, Nb, Ta, W, Mo, Fe, Co, Cr, and m is the number of BO 6 octahedrals in the pseudoperovskite block (m=2, 3, 4, 5) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Bi 4 Ti 3 O 12 (BIT) is one of the more extensively studied materials among the BLSF family due to its large spontaneous polarization along the a-axis (approximately 50 μC/cm 2 ), [4] low processing temperature, high Curie temperature, and lead-free composition.…”