The dielectric and leakage current behavior of CoFe2O4-BaTiO3 composite films prepared by combining method of sol-gel and electrophoretic deposition

Polycrystalline Bi 0.975 La 0.025 Fe 0.975 Ni 0.025 O 3 (BLFNO) film is fabricated on Pt / Ti / SiO 2/ Si (111) substrate by sol–gel method. It is found that the well-crystallized BLFNO film is polycrystalline, and the Pt / BLFNO / Pt capacitor possesses good ferroelectric properties with remnant polarization of 74 μC/cm2 at electric field of 833 kV/cm. Moreover, it is also found that the leakage current density of the Pt / BLFNO / Pt capacitor increases with the increase of measurement temperature ranging from 100 to 300 K. The leakage density of the Pt / BLFNO / Pt capacitor satisfies space-charge-limited conduction (SCLC) at higher electric field and shows little dependence on voltage polarity and temperature, but shows polarity and temperature dependence at lower applied electric field. With temperature increasing from 100 to 300 K at lower applied electric field, the most likely conduction mechanism is from Ohmic behavior to SCLC for positive biases, but no clear dominant mechanism for negative biases is shown.

Download Full-text

Dielectric and ferroelectric properties of CoCr2O4 nanoceramics

Journal of Advanced Dielectrics ◽

10.1142/s2010135x19500152 ◽

2019 ◽

Vol 09 (03) ◽

pp. 1950015 ◽

Cited By ~ 1

Author(s):

Pankaj Choudhary ◽

P. Saxena ◽

A. Yadav ◽

V. N. Rai ◽

A. Mishra

Keyword(s):

Leakage Current ◽

Ferroelectric Properties ◽

Sol Gel ◽

Complex Impedance ◽

Interfacial Polarization ◽

Nyquist Plot ◽

Dielectric Parameters ◽

Electron Conduction ◽

Auto Combustion ◽

Current Behavior

CoCr2O4 nanoceramics are prepared by sol–gel auto combustion method. Synchrotron X-ray diffraction analysis affirms the single-phase pristine cubic structure with space group [Formula: see text]. Debye–Scherrer method estimates the crystallite size of main intense peak to be [Formula: see text][Formula: see text]nm. Prominent bands obtained in infrared spectra at 448 and 599[Formula: see text]cm[Formula: see text] are due to metal–oxygen stretching bond present at tetrahedral and octahedral sites. Dielectric parameters decrease as frequency increases from [Formula: see text] to [Formula: see text][Formula: see text]Hz that can be interpreted by Maxwell–Wagner-type interfacial polarization. Complex impedance spectra (Nyquist plot) reveal arc like behavior, which is mainly due to intergrain (grain boundary) resistance that also exhibits conducting nature of the nanoceramics. Weak ferroelectricity is mainly associated with the partial reversal of the polarization. Leakage current behavior follows the Ohmic and Child square law. Electron conduction process was interpreted by space-charge limited current (SCLC) mechanism. Leakage current behavior observed in cobalt chromite nanoceramics is mainly attributed to the oxygen vacancies.

Download Full-text

Effect of hydrogen on true leakage current characteristics of (Pb,La)(Zr,Ti)O3 thin-film capacitors with Pt- or Ir-based top electrodes

Journal of Materials Research ◽

10.1557/jmr.2001.0163 ◽

2001 ◽

Vol 16 (4) ◽

pp. 1185-1189 ◽

Cited By ~ 7

Author(s):

Soon-Gil Yoon ◽

Dwi Wicaksana ◽

Dong-Joo Kim ◽

Seung-Hyun Kim ◽

A. I. Kingon

Keyword(s):

Leakage Current ◽

Sol Gel ◽

Conducting Phase ◽

Thin Film Capacitors ◽

Proposed Model ◽

Injection Model ◽

Recovery Anneal ◽

Current Characteristics ◽

Plzt Thin Films ◽

Current Behavior

The degradation behavior of polarization and leakage current characteristics of sol-gel-derived (Pb,La)(Zr,Ti)O3 (PLZT) thin films, with Pt, Ir, and IrO2 top electrodes, by annealing under a 4% H2/96% N2 atmosphere were investigated. The leakage current behaviors of Pt/PLZT/Pt and IrO2/PLZT/Pt capacitors annealed at 300 °C for 20 min in 4% H2 were well consistent with the space-charge-influenced injection model proposed. However, IrO2/PLZT/Pt capacitors recovered at 700 °C for 10 min in Ar ambient after hydrogen anneal were not consistent with the proposed model because a conducting phase of IrPb was formed between the top electrode and PLZT during the recovery anneal at 700 °C in Ar ambient and modified the Schottky barrier height. The true leakage current behavior of IrO2/PLZT/Pt capacitors recovered after hydrogen forming are similar to those of Ir/PLZT/Pt capacitors without the hydrogen-forming gas anneal. The P–E loops of Pt/PLZT/Pt and Ir/PLZT/Pt capacitors showed good recovery through recovery anneal after H2 treatment. However, IrO2/PLZT/Pt capacitors depended on the recovery anneal atmosphere (Ar or O2).

Download Full-text

Electrical properties and leakage current behavior of un-doped and Ti-doped lead zirconate thin films synthesized by sol–gel method

Thin Solid Films ◽

10.1016/j.tsf.2007.08.046 ◽

2008 ◽

Vol 516 (12) ◽

pp. 4002-4010 ◽

Cited By ~ 13

Author(s):

Ebru Mensur Alkoy ◽

Tadashi Shiosaki

Keyword(s):

Thin Films ◽

Electrical Properties ◽

Leakage Current ◽

Sol Gel ◽

Lead Zirconate ◽

Gel Method ◽

Sol Gel Method ◽

Current Behavior

Download Full-text

Synthesis and Stabilization of BaTiO3/CoFe2O4 Ferrocolloids

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.415-417.362 ◽

2011 ◽

Vol 415-417 ◽

pp. 362-367

Author(s):

Dong Xiang Zhou ◽

Fei Shi ◽

Shu Ping Gong ◽

Qiu Yun Fu

Keyword(s):

Electrophoretic Deposition ◽

Sol Gel ◽

Average Particle Size ◽

Mixed Solvents ◽

Composite Films ◽

Deposition Process ◽

Nano Particles ◽

Average Particle ◽

Two Phase ◽

The Impact

In this article, nanocomposites of BaTiO3/CoFe2O4 have been prepared by sol-gel technique. The samples have been calcined at various temperatures ranging from 500 to 900 °C and then the microstructure of the composite nano-particles was studied. XRD, SEM analysis showed the powders can form the two phase composite system of BaTiO3 and CoFe2O4 and the average particle size of the crystalline phases is 50nm at sintering temperature of 800 °C. In addition, we have studied the effects of different solvents and mixed solvents on the stability of the nanocomposites suspensions. Results of sediment volumes and conductivity showed under ultrasonic agitation for at least 25 min, suspensions of the BaTiO3/CoFe2O4 in ethanol-acetylacetone (1:1 in volume) were most stable (the sediment volumes is 0.6cm3/0.4g, the conductivity is 9μS/cm). Electrophoretic deposition (EPD) was utilized for preparation of magnetoelectric (ME) composite films, the impact of deposition time and deposition voltage on electrophoretic deposition process was investigated. The obtained ME composite films exhibited good ferroelectric and ferromagnetic properties, which can meet the demand of ME devices.

Download Full-text

Simple Electrode-Barrier Structure Using Ir for Integration of PZT-Based High-Density Nonvolatile Memories

MRS Proceedings ◽

10.1557/proc-541-197 ◽

1998 ◽

Vol 541 ◽

Cited By ~ 2

Author(s):

Kwang B. Lee ◽

S. Tirumala ◽

Y. Song ◽

Sang O. Ryu ◽

Seshu B. Desu

Keyword(s):

Thin Films ◽

Leakage Current ◽

Electrical Contact ◽

Sol Gel ◽

Hysteresis Loops ◽

Barrier Properties ◽

Pzt Thin Films ◽

Nonvolatile Memories ◽

Si Wafer ◽

Current Behavior

AbstractWe have investigated the electrode-barrier properties of Ir for PZT-based nonvolatile memories. Ir layer was rf-sputtered onto a poly-Si coated Si wafer. PZT thin films were deposited on Ir/poly-Si/SiO2/Si by means of sol-gel spin coating. Highly c-axis oriented perovskite PZT thin films were obtained, which might be due to the interface-controlled growth. We found that Ir in itself acted as an oxygen barrier, which was confirmed from the measurement of P-E hysteresis loops with the electrical contact between top-electrode and bottom-poly-Si. Remanent polarization and coercive field of 1rO2/PZT/Ir/poly-Si capacitor were 20 μC/cm2and 30 kV/cm, respectively and the capacitor showed negligible polarization fatigue up to 1011 switching repetitions. However, the leakage current density at the field of larger than 80 kV/cm was high, which was believed to be related to the unknown phase in PZT caused by the reaction of PbO with bottom-Ir. Such high leakage current behavior could be successively improved by the insertion of vacuum-annealed IrOx buffer layer between PZT/Ir. The electrical properties of IrOx/PZT/annealed-IrO2Ir/poly-Si capacitors are also discussed.

Download Full-text

Investigation of the Effect of Cerium Doping on the Electrical Properties and Leakage Current Behavior of Lead Zirconate Thin Films Derived by the Sol-Gel Method

Journal of the American Ceramic Society ◽

10.1111/j.1551-2916.2008.02858.x ◽

2009 ◽

Vol 92 (2) ◽

pp. 396-404 ◽

Cited By ~ 13

Author(s):

Ebru Mensur Alkoy ◽

Tadashi Shiosaki

Keyword(s):

Thin Films ◽

Electrical Properties ◽

Leakage Current ◽

Sol Gel ◽

Lead Zirconate ◽

Gel Method ◽

Sol Gel Method ◽

Cerium Doping ◽

Current Behavior

Download Full-text

Significantly Improved Dielectric Performance of Poly(1-butene)-Based Composite Films via Filling Polydopamine Modified Ba(Zr0.2Ti0.8)O3-Coated Multiwalled Carbon Nanotubes Nanoparticles

Polymers ◽

10.3390/polym13020285 ◽

2021 ◽

Vol 13 (2) ◽

pp. 285

Author(s):

Lingfei Li ◽

Qiu Sun ◽

Xiangqun Chen ◽

Zhaohua Jiang ◽

Yongjun Xu

Keyword(s):

Carbon Nanotubes ◽

Dielectric Constant ◽

Energy Storage ◽

Composite Film ◽

Multiwalled Carbon Nanotubes ◽

Sol Gel ◽

Composite Films ◽

Weak Electric Field ◽

Multiwalled Carbon ◽

Dielectric Performance

The low dielectric constant of the nonpolar polymer poly(1-butene) (PB-1) limits its application as a diaphragm element in energy storage capacitors. In this work, Ba(Zr0.2Ti0.8)O3-coated multiwalled carbon nanotubes (BZT@MWCNTs) were first prepared by using the sol–gel hydrothermal method and then modified with polydopamine (PDA) via noncovalent polymerization. Finally, PB-1 matrix composite films filled with PDA-modified BZT@MWCNTs nanoparticles were fabricated through a solution-casting method. Results indicated that the PDA-modified BZT@MWCNTs had good dispersion and binding force in the PB-1 matrix. These characteristics improved the dielectric and energy storage performances of the films. Specifically, the PDA-modified 10 vol% BZT@ 0.5 vol% MWCNTs/PB-1 composite film exhibited the best dielectric performance. At 1 kHz, the dielectric constant of this film was 25.43, which was 12.7 times that of pure PB-1 films. Moreover, its dielectric loss was 0.0077. Furthermore, under the weak electric field of 210 MV·m−1, the highest energy density of the PDA-modified 10 vol% BZT@ 0.5 vol% MWCNTs/PB-1 composite film was 4.57 J·cm−3, which was over 3.5 times that of PB-1 film (≈1.3 J·cm−3 at 388 MV·m−1).

Download Full-text

Optical Isomerization and Photo-Patternable Properties of GeO2/Ormosils Organic-Inorganic Composite Films Doped with Azobenzene

Coatings ◽

10.3390/coatings11070818 ◽

2021 ◽

Vol 11 (7) ◽

pp. 818

Author(s):

Xuehua Zhang ◽

Qian Wang ◽

Shun Liu ◽

Wei Zhang ◽

Fangren Hu ◽

...

Keyword(s):

Optical Waveguide ◽

Data Storage ◽

Optical Switching ◽

Sol Gel ◽

Composite Films ◽

Optical Data Storage ◽

Optical Data ◽

Single Chip ◽

Coating Method ◽

Inorganic Composite

GeO2/organically modified silane (ormosils) organic-inorganic composite films containing azobenzene were prepared by combining sol-gel technology and spin coating method. Optical waveguide properties including the refractive index and thickness of the composite films were characterized by using a prism coupling instrument. Surface morphology and photochemical properties of the composite films were investigated by atomic force microscope and Fourier transform infrared spectrometer. Results indicate that the composite films have smooth and neat surface, and excellent optical waveguide performance. Photo-isomerization properties of the composite films were studied by using a UV–Vis spectrophotometer. Optical switching performance of the composite films was also studied under the alternating exposure of 365 nm ultraviolet light and 410 nm visible light. Finally, strip waveguides and microlens arrays were built in the composite films through a UV soft imprint technique. Based on the above results, we believe that the prepared composite films are promising candidates for micro-nano optics and photonic applications, which would allow directly integrating the optical data storage and optical switching devices onto a single chip.

Download Full-text

The Preparation and Photocatalytic Activity of SWNTs Doped ZnO/TiO2 Compound Films

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.97-101.1611 ◽

2010 ◽

Vol 97-101 ◽

pp. 1611-1615 ◽

Cited By ~ 1

Author(s):

Qing Wang ◽

Xin Li Li ◽

Wei Nie ◽

Yong Mei Xia ◽

Jian Feng Dai

Keyword(s):

Photocatalytic Activity ◽

Absorption Spectra ◽

Sol Gel ◽

Composite Films ◽

Wavelength Region ◽

Tio2 Films ◽

X Ray Diffraction ◽

Sol Gel Process ◽

Doped Zno ◽

Walled Carbon Nanotubes

The ZnO/TiO2 composite films were deposited over glass using spin coating technique by sol-gel process. Single-walled carbon nanotubes (SWNTs) were used to modify the ZnO/TiO2 films successfully in this paper. The structure and composition of the ZnO/TiO2 composite and SWNTs doped ZnO/TiO2 composite were characterized by X-ray diffraction (XRD). The morphology of samples was characterized by scanning electron microscopy (SEM). The photocatalytic activity was investigated by photocatalytic degradation of aqueous methyl orange under ultraviolet (UV) radiation. The UV-vis absorption spectra of the ZnO/TiO2 films and SWNTs doped ZnO/TiO2 films in the wavelength region 200~800 nm were obtained. The results indicate that the SWNTs addition can decrease the grain size of ZnO/TiO2, which can enhance the photocatalytic activity. UV-vis absorption spectra of SWNTs-ZnO/TiO2 showed obvious blue shifts compared with ZnO/TiO2. The optimal amount of doping SWNTs is 1% according to this research. The enhanced mechanism of the SWNTs for the photocatalytic activity in ZnO/TiO2 films was analyzed in this article.

Download Full-text