Search

Pure BiFeO3(BFO) and Gd-transition metal co-doped (Bi0.9Gd0.1)(Fe0.975B0.025)O3±δ(B= Ni, Mn, Cu, Ti, and V, denoted by BGdFNi, BGdFMn, BGdFCu, BGdFTi, and BGdFV) films were deposited by using a chemical solution deposition. Enhanced electrical properties were observed for the co-doped films. The BGdFMn film showed the largest 2Prvalue (105.3 μC/cm2at 1470 kV/cm) and the smallest leakage current density (1.49 × 10−5A/cm2at 100 kV/cm). The enhanced electrical properties for the co-doped films are related to the decrease of oxygen vacancies, the stabilization of perovskite structure, and the lattice distortion by the doping elements. [ABSTRACT FROM AUTHOR]

Pure Bi6Fe2Ti3O18and vanadium (V) doped Bi6Fe2Ti3O18(Bi5.99Fe2Ti2.75V0.03O18) thin films were prepared on Pt(111)/Ti/SiO2/Si(100) substrates by a chemical solution deposition method. The Bi5.99Fe2Ti2.75V0.03O18thin film exhibited improved electrical and multiferroic properties, such as leakage current densities, dielectric properties, ferroelectric and ferromagnetic properties. We consider that the improved properties might be related to the reduced concentration of oxygen vacancies and the decreased mobility of oxygen vacancies by V doping. [ABSTRACT FROM PUBLISHER]

We have evaluated the ferroelectric and electrical properties of pure BiFeO3(BFO) and (Bi0.9Ho0.1)(Fe0.975Ti0.025)O3+δ(BHFTO) thin films on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method. The improved electrical properties were observed in the BHFTO thin film. The leakage current density of the co-doped BHFTO thin film showed three order lower than that of the pure BFO, 1.22 × 10−6A/cm2at 100 kV/cm. The remnant polarization (2Pr) and the coercive electric field (2Ec) of the BHFTO thin film were 61 μC/cm2and 1190 kV/cm at an applied electric field of 800 kV/cm and at a frequency of 1 kHz and these values decreased with increasing measurement frequency, 35 μC/cm2and 920 kV/cm at 10 kHz, respectively. Also, the 2Prand the 2Ecvalues were fairly saturated above 30 kHz. [ABSTRACT FROM PUBLISHER]

Pure Bi5FeTi3O15and its doped compounds, such as Bi4.15La0.75FeTi3O15and Bi4.15Nd0.85FeTi3O15thin films, were prepared on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method. The crystalline structures and the surface morphologies of the thin films were identified by using an X-ray diffractometry, a Raman spectroscopy, and a scanning electron microscopy. In addition, the comprehensive electrical properties of the thin films, such as ferroelectric hysteresis loops and leakage current densities, were characterized by using a precision materials analyzer and an electrometer at room temperature, respectively. [ABSTRACT FROM AUTHOR]

We prepared pure BiFeO3(BFO) and co-doped (Bi0.9Nd0.1)(Fe0.975V0.025)O3+δ(BNFVO) thin films on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method. Improved electrical properties were observed in the co-doped BNFVO thin film. The leakage current density of the co-doped BNFVO thin film was four orders of magnitude lower than that of the pure BFO, 2.6 × 10−7A/cm2at 100 kV/cm. The remnant polarization (2Pr) and the coercive electric field (2Ec) of the co-doped BNFVO thin film were 56 μC/cm2and 1393 kV/cm at an applied electric field of 1110 kV/cm and at a frequency of 1 kHz, and the values decreased with increasing measurement frequency to 18 μC/cm2and 1282 kV/cm at 10 kHz, respectively. We also confirmed that the remnant polarization (2Pr) and the coercive electric field (2Ec) were fairly saturated above a measurement frequency of 20 kHz for the BNFVO thin film. [ABSTRACT FROM AUTHOR]

Bismuth ferrite BiFeO3(BFO) and holmium (Ho)-chromium (Cr) co-doped bismuth ferrite (Bi0.9Ho0.1)(Fe0.975Cr0.025)O3, (BHFCr) thin films were deposited on Pt(111)/Ti/SiO2/Si substrates by using a chemical solution deposition method. Effects of Ho and Cr co-doping on the micro-structures, ferroelectric properties and leakage current densities of the thin films were investigated. The single-phase rhombohedral perovskite structures of the thin films were confirmed by an X-ray diffraction analysis. From the electrical property studies, the BHFCr thin film showed enhanced electrical properties compared to the BFO thin film. The improved electrical properties of the BHFCr thin film are correlated with greatly improved microstructure, stabilization of the perovskite structure and defects compensation. [ABSTRACT FROM AUTHOR]

(Eu, Mn) co-doped bismuth ferrite [(Bi0.9Eu0.1)(Fe0.9Mn0.1)O3 (BEFMO)] thin films were deposited on Pt(111)/Ti/SiO2/Si substrates by using a chemical solution deposition method. The coated films were annealed in N2, air and O2 atmospheres at 550°C for 30 min. Effects of annealing atmosphere on the crystal structure, ferroelectric properties and leakage current density of the BEFMO thin films were investigated. The single-phase rhombohedral perovskite crystal structure of all the samples was confirmed by x-ray diffraction analysis. From the electrical studies, the BEFMO thin film annealed in air atmosphere showed better electrical properties than O2 and N2 atmosphere annealed samples. The largest remnant polarization 96.4 μC/cm2 at an electric field 1060 kV/cm was obtained from the BEFMO thin film annealed in air. [ABSTRACT FROM AUTHOR]

Thin films of BiFeO3 (BFO), Bi0.9Eu0.1Fe0.975Cu0.025O3-δ (BEuFC) and Bi0.9Dy0.1 Fe0.975Cu0.025O3-δ (BDyFC) were prepared on Pt(111)/Ti/SiO2/Si(100) substrates via a chemical solution deposition method. X-ray diffraction and Raman studies show distorted rhombohedral perovskite crystal structure for all the samples. Micro structural features and morphological changes of the BFO, BEuFC and BDyFC were examined by using a FE-SEM analysis. The leakage current density was found to be greatly reduced for the BEuFC and the BDyFC thin films. The largest remnant polarization (2Pr) 68 μC/cm2 (at 1336 kV/cm) and the lowest coercive field (2Ec) 845 kV/cm (at 931 kV/cm) were observed from the BEuFC and the BDyFC thin films, respectively. [ABSTRACT FROM AUTHOR]

The structural and electrical properties of BiFeO3 (BFO) and rare earth metal ions (Re) co-substituted (Bi0.9Re0.1)(Fe0.9Mn0.1)O3-δ (Re = Nd, Sm, Ce and Tb) thin films prepared on Pt(111)/Ti/SiO2/Si(100) substrates via a chemical solution deposition method were investigated. The significant decrease of leakage current density and improved ferroelectric properties were observed from the co-substituted thin films. The largest remnant polarization (2Pr) (61.7 μC/cm2) and the lowest coercive field (2Ec) 657 kV/cm at 931 kV/cm were measured from the (Bi0.9Ce0.1)(Fe0.9Mn0.1)O3-δ thin film. The leakage current density value of (Bi0.9Sm0.1)(Fe0.9Mn0.1)O3-δ thin film (3.29 × 10−5A/cm2) was found to be two order lower than that of the pure BFO. [ABSTRACT FROM AUTHOR]

Ferroelectric K0.5Bi4.5Ti4O15 (KBTi) and Cr-doped K0.5Bi4.5Ti4O15 ((K0.5Bi4.5Ti3.97 Cr0.03O15-δ), (KBTC)) thin films were prepared on Pt(111)/Ti/SiO2/Si substrates by using a chemical solution deposition method. The thin films were annealed at 750°C for 3 min by a rapid thermal annealing process under oxygen atmosphere. Compared to pure KBTi thin film, there was no structural change while improved ferroelectric and leakage current properties were observed. The values of remnant polarization (2Pr ) and coercive field (2Ec ) were 50.9 μC/cm2 and 244 kV/cm at an applied electric field of 300 kV/cm, respectively. The 2Pr we observed is compatible with that of doped bismuth layer-structured ferroelectric thin films. Leakage current density was 6.00 × 10−7 A/cm2 at 200 kV/cm. The enhanced properties of KBTC could be explained by a defect dipole (Cr′Ti-V) and increased average grain size. [ABSTRACT FROM AUTHOR]

Ferroelectric Na0.5Bi4.5Ti4O15 (NaBTi) thin films, selectively controlled in c-axis and random orientation, were fabricated on a Pt(111)/Ti/SiO2/Si(100) substrate by using a chemical solution deposition method. The preferred orientation of the thin films annealed at 750°C under oxygen atmosphere was confirmed by X-ray diffraction and scanning electron microscope studies. We found that ferroelectric, dielectric, and leakage current properties were strongly related to the crystallographic orientation of NaBTi thin films; the randomly oriented NaBTi thin film exhibited better properties than the c-axis oriented thin film. The values of remnant polarization (2Pr), dielectric constant, and leakage current density were 21 μC/cm2 at 300 kV/cm, 630 at 100 kHz, and 7.4 × 10-6 A/cm2 at 100 kV/cm for the randomly oriented thin film, respectively, and 6 μC/cm2, 420, and 1.1 × 10-1 A/cm2 for the c-axis oriented thin film, respectively. Also, no polarization fatigue was observed in both NaBTi thin films up to 107 switching cycles. [ABSTRACT FROM AUTHOR]

SrBi5FeTi4O18 (SBFT) thin films were prepared on a Pt(111)/Ti/SiO2/Si(100) substrate using a chemical solution deposition method and annealed at 650°C under oxygen atmosphere. It was found that the polycrystalline SBFT thin film exhibits good ferroelectric properties. The values of remnant polarization (2Pr) and coercive electric field (2Ec) were 33 μ C/cm2 and 150 kV/cm at an applied electric field of 250 kV/cm, respectively. Leakage current density of the thin film was 106 A/cm2 at 100 kV/cm. The values of dielectric constant and dielectric loss were 470 and 0.05 at 1 kHz, respectively. No significant polarization fatigue was observed up to 1.44 × 1010 switching cycles. Also weak ferromagnetic properties were observed. [ABSTRACT FROM AUTHOR]

Cr-substituted BiFeO3 (BFCr-3 mol%) thin films were deposited on Pt(200)/TiO2/SiO2/Si substrates by a chemical solution deposition. The coated films were annealed in the temperature range of 500°C∼ 600°C for 30 min under nitrogen atmosphere. The electrical properties of BFCr thin films were found to be sensitive to the annealing temperature. It was found that BFCr thin films exhibited good ferroelectric properties, such as an improved leakage-current density and P-E hysteresis characteristics. The BFCr thin film annealed at 525°C exhibits a low leakage current density of 9.2 × 10- 7 A/cm2 at an applied electric field of 100 kV/cm. The films exhibited a well-saturated hysteresis loop with a remanent polarization (Pr) of 47 μC/cm2 at room temperature. The reason for the improved leakage current and ferroelectric properties in BFCr thin films can be attributed to the effects of increased grain size and oxygen vacancies reduced by Cr doping. [ABSTRACT FROM AUTHOR]

5 mol % La3 +, Nd3 + or Y3 +-cosubstituted BiFe0.97Cr0.03O3 thin films (denoted by BLaFCr, BNdFCr, and BYFCr, respectively) have been successfully deposited on Pt (200)/TiO2/SiO2/Si substrates by a chemical solution deposition method. Well-saturated ferroelectric hysteresis loops and low leakage current densities have been observed in BLaFCr, BNdFCr, and BYFCr thin films with single-phase structure. The values of remanent polarization (Pr) and coercive field (Ec) were 64 μ C/cm2 and 275 kV/cm, 61 μC/cm2 and 290 kV/cm, and 31 μ C/cm2 and 315 kV/cm for BLaFCr, BNdFCr and BYFCr thin films at the maximum electric field of 712 kV/cm, respectively. In the present study, the differences in values of Pr seem to be related to the doped ionic radii. [ABSTRACT FROM AUTHOR]