Rui Fang Liu

Ferroelectric Properties of Bismuth Titanate Ceramics by Sm3+/V5+ Substitution

The ferroelectricity of Bi3.25Sm0.75Ti3O12 (BST), and Bi3.25Sm0.75Ti2.97V0.03O12 (BSTV) ceramics prepared at 1100°C by a conventional ceramic technique was investigated. These ceramics possess random-oriented polycrystalline structure. The remanent polarization (Pr) and coercive field (Ec) of the BST ceramics are 16 µC/cm2 and 64kV/cm, respectively. Furthermore, V substitution improves the Pr value of the BST ceramics up to 25 μC/cm2, which is much larger than that of the BST ceramics. Therefore, co-sustitution of Sm and V in is effective for the improvement of the ferroelectricity of Bi4Ti3O12 ceramic.

Ferroelectric Properties and Microstructures of Tb2O3-Doped Bismuth Titanate Ceramics

The electrical properties of Tb2O3-doped bismuth titanate,Bi4-xTbxTi3O12 (BTT) ceramics prepared by a conventional electroceramic technique have been investigated. XRD analyses indicted Bi-layered perovskite structure in all samples, and revealed that Bi ions were only substituted near the Ti-O octahedron layers by Tb ions. SEM micrographs show randomly oriented and plate-like morphology. The remanent polarization ( Pr ) and coercive field ( Ec ) of the BTT ceramics with x=0.75 were above 16μC/cm2 and 75KV/cm, respectively. The large value of remanent polarization and low coercive field of Tb-doped bismuth titanate ceramics promote these materials to potential applications.

Impedance Spectra and Ferroelectric Properties of Bismuth Titanate Ceramics by Nd3+/V5+ Substitution

The ferroelectricity of Bi3.25Nd0.75Ti3O12 (BNT), and Bi3.25Nd0.75Ti2.97V0.03O12 (BNTV) ceramics prepared at 1100°C by a conventional ceramic technique was investigated. These ceramics possess random-oriented polycrystalline structure. The remanent polarization (Pr) and coercive field (Ec) of the BNT ceramics are 16 µC/cm2 and 65kV/cm, respectively. Furthermore, V substitution improves the Pr value of the BNTV ceramics up to 23 μC/cm2, which is much larger than that of the BNT ceramics. Therefore, co-sustitution of Nd and V in Bi4Ti3O12 ceramic is effective for the improvement of its ferroelectricity.

Ferroelectric Properties of Bismuth Titanate Ceramics by Tb2O3/V2O5 Substitution

The ferroelectricity of Bi3.2Tb0.8Ti3O12 (BTT) and Bi3.2Tb0.8Ti2.97V0.03O12 (BTTV) ceramics prepared at 1100°C by a conventional ceramic technique was investigated. These ceramics possess random-oriented polycrystalline structure. The remanent polarization (Pr) and coercive field (Ec) of the BTT ceramics are 16 μC/cm2 and 75kV/cm, respectively. Furthermore, V substitution improves the Pr value of the BTT ceramics up to 26 μC/cm2, which is much larger than that of the BTT ceramics. Therefore, co-sustitution of Tb and V in Bi4Ti3O12 (BIT) ceramic is effective for the improvement of its ferroelectricity.

Effect of Gd Substitution on Electrical Characteristics and Microstructures of Bi4Ti3O12 Ceramics

The electrical properties of Gd-doped bismuth titanate Bi4-xGdxTi3O12 (BGT) ceramics prepared by a conventional electroceramic technique were investigated. XRD analyses revealed Bi-layered perovskite structure in all samples. SEM micrographs showed randomly oriented and plate-like morphology. For the ceramics with x=0.25 and 1.0 the current-voltage characteristics exhibited negative differential resistance behaviors and their P-E hysteresis loops were characterized by large leakage current, whereas for the ceramics with x=0.5 and 0.75 the current-voltage characteristics showed simple ohmic behaviors and their P-E hysteresis loops were the saturated and undistorted hysteresis loops. The remanent polarization ( Pr ) and coercive field (Ec) of the BGT ceramic with x=0.8 were above 16μC/cm2 and 70KV/cm , respectively.

Ferroelectric Characteristics of Bi4-xErxTi3O12 Ceramics

The electrical properties of Er2O3-doped bismuth titanate,Bi4-xErxTi3O12 (BET) ceramics prepared by a conventional electroceramic technique were investigated. XRD analyses revealed Bi-layered perovskite structure in all samples. SEM micrographs showed randomly oriented and plate-like morphology. For the samples with x=0.4 and 1.0 P-E hysteresis loops were characterized by large leakage current, whereas for the samples with x=0.6 and 0.8 P-E hysteresis loops were the saturated and undistorted hysteresis loops. The remanent polarization ( Pr ) and coercive field (Ec) of the BET ceramic with x=0.8 were above 20μC/cm2 and 65KV/cm , respectively.

Ferroelectric Property and Microstructures of La-Doped Bi4Ti3O12 Thin Films

La-doped bismuth titanate (Bi4-xLaxTi3O12: BLT) and pure Bi4Ti3O12 (BIT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. For the samples with x=0.25 and 1.0 the current-voltage characteristics exhibited negative differential resistance behaviors and their P-V hysteresis loops were characterized by large leakage current, whereas for the samples with x=0.5 and 0.75 the current-voltage characteristics showed simple ohmic behaviors and their P-V hysteresis loops were the saturated and undistorted hysteresis loops. The remanent polarization ( Pr ) and coercive field (Ec) of the BLT ceramic with x=0.75 were above 20μC/cm2 and 85KV/cm , respectively.

Electrical Characterization and Microstructures of Bi3.3Tb0.6Ti3O12 and Bi3.3Tb0.6Ti2.97V0.03O12 Thin Films

Bi3.3Tb0.6Ti3O12(BTT), Bi3.3Tb0.6Ti2.97V0.03O12(BTTV), and pure Bi4Ti3O12 (BIT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. The experimental results indicated that Tb doping into BIT also result in a remarkable improvement in ferroelectric property. The remanent polarization (Pr) and coercive field (Ec) of the BTT film were 25 μC/cm2 and 85 kV/cm, respectively. Furthermore, V substitution improves the Pr value of the BTVT film up to 35 μC/cm2, which is much larger than that of the BTT film.

Ferroelectric Properties of Bismuth Titanate Ceramics by Er3+/V5+ Substitution

The ferroelectricity of Bi3.2Er0.8Ti3O12 (BET), and Bi3.2Er0.8Ti2.97V0.03O12 (BETV) ceramics prepared at 1100°C by a conventional ceramic technique was investigated. These ceramics possess random-oriented polycrystalline structure. The remanent polarization (Pr) and coercive field (Ec) of the BET ceramics are 18 µC/cm2 and 64kV/cm, respectively. Furthermore, V substitution improves the Pr value of the BETV ceramics up to 30 μC/cm2, which is much larger than that of the BET ceramics. Therefore, co-sustitution of Er and V in Bi4Ti3O12 (BIT) ceramic is effective for the improvement of its ferroelectricity.

Ferroelectric Properties of Bismuth Titanate Ceramics by Tb3+,4+/V5+ Substitution

The Ferroelectric properties and Microstructures of Bi3.3Tb0.6Ti3O12 (BTT) and Bi3.3Tb0.6Ti2.97V0.03O12 (BTTV) ceramics prepared at 1100°C by a conventional ceramic technique were investigated. These ceramics possess random-oriented polycrystalline structure. The remanent polarization (Pr) and coercive field (Ec) of the BTT ceramics are 23µC/cm2 and 80kV/cm, respectively. Furthermore, V substitution improves the Pr value of the BTTV ceramics up to 35μC/cm2, which is larger than that of the BTT ceramics. Therefore, co-sustitution of Tb and V in Bi4Ti3O12 (BIT) ceramic is effective for the improvement of its ferroelectricity.