Structural, Dielectric and Electrical Properties of Sol-Gel Auto-Combustion Technic of CuFeCr0.5Ni0.5O4 Ferrite

Abstract The CuFeCr0.5Ni0.5O4 (CFO) compound was synthesized using sol-gel reaction combustion technic. The structural analysis showed that the obtained composites have a polycrystalline nature and the cubic spinel structure ( space group). Microstructural analysis revealed the formation of spherical and elongated grains of our sample. The dielectric and electrical transport properties of CuFeCr0.5Ni0.5O4 were investigated in detail by Ac impedance spectroscopy in a wide range of temperature (200 K-400 K) and frequency (100Hz to100KHz). Our results show that the electrical modulus and impedance studies confirm the presence of a relaxation phenomenon with non-Debye type in the prepared sample. The activation energy Edc estimated from the slope of the linear fit plot is equal to 0.158 eV with frequency of 100Hz and 0.126 eV with frequency of 1MHz at temperature range 200K-400K. Close activation energies values were found from analyzes of relaxation time and dc-conductivity indicating that the relaxation and the conduction processes may be attributed to the presence of free carrier charges and impurities at the grain boundaries. The conduction process for samples is described by the NSPT model. The complex impedance analyses and modulus formalism confirm a grain and grain boundary mechanism contributing to the dielectric properties. The real and the imaginary parts of the impedance are well ﬁtted to equivalent electrical circuit (Rg+ Rgb//CPEgb) was used for modeling the Nyquist data.

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Effect of Sintering on Structural and Transport Properties on Nanosized Pr0.85Na0.15MnO3

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1107.272 ◽

2015 ◽

Vol 1107 ◽

pp. 272-277 ◽

Cited By ~ 1

Author(s):

Siau Wei Ng ◽

Kean Pah Lim ◽

S.A. Halim ◽

Hassan Jumiah ◽

Albert H.M. Gan ◽

...

Keyword(s):

Grain Size ◽

Transport Properties ◽

Electrical Transport ◽

Boundary Effect ◽

Sol Gel ◽

Magnetic Layer ◽

Electrical Transport Properties ◽

Orthorhombic Crystal ◽

Orthorhombic Crystal Structure ◽

Semiconductor Behavior

We have investigated the structural, microstructure and electrical transport properties of nanosized Pr0.85Na0.15MnO3 (PNMO) synthesized by sol-gel technique and sinter from 600°C to 1000°C. The grain size increases from 67 nm (S600) up to 284 nm (S1000) due to the grain growth during heat treatment. XRD showed that single phase orthorhombic crystal structure of PNMO is fully forms started at 600°C. The resistivity decreased with the increased of grain size and crystallite size due to the reduction of grain boundary effect (dead magnetic layer) which improved their grain conductivity.All samples showed semiconductor behavior where their metal insulator transition temperatures (TMIT) were estimated to be lower than 80K.

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Sol-Gel Processed Yttrium-Doped SnO2 Thin Film Transistors

Electronics ◽

10.3390/electronics9020254 ◽

2020 ◽

Vol 9 (2) ◽

pp. 254 ◽

Cited By ~ 2

Author(s):

Changmin Lee ◽

Won-Yong Lee ◽

Hyunjae Lee ◽

Seunghyun Ha ◽

Jin-Hyuk Bae ◽

...

Keyword(s):

Thin Film ◽

Oxygen Vacancy ◽

Electrical Transport ◽

Thin Film Transistors ◽

Vacancy Concentration ◽

Operation Mode ◽

Sol Gel ◽

Sno2 Thin Film ◽

Oxygen Vacancy Concentration ◽

Electrical Transport Properties

Y-doped SnO2 thin film transistors were successfully fabricated by means of sol-gel process. The effect of Y concentration on the structural, chemical, and electrical properties of sol-gel-processed SnO2 films was investigated via GIXRD, SPM, and XPS; the corresponding electrical transport properties of the film were also evaluated. The dopant, Y, can successfully control the free carrier concentration by suppressing the formation of oxygen vacancy inside SnO2 semiconductors due to its lower electronegativity and SEP. With an increase of Ywt%, it was observed that the crystallinity and oxygen vacancy concentration decreased, and the operation mode of SnO2 thin film transistor changed from accumulation (normally on) to enhancement mode (normally off) with a positive Vth shift.

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Magnetic and electrical transport properties of Sr2Ti1−xCoxO4 ceramics by sol–gel

Modern Physics Letters B ◽

10.1142/s0217984917501950 ◽

2017 ◽

Vol 31 (17) ◽

pp. 1750195

Author(s):

Li Zhang ◽

Yibao Li ◽

Zhen Tang ◽

Yan Deng ◽

Hui Yuan ◽

...

Keyword(s):

Transport Properties ◽

Electrical Transport ◽

Low Temperatures ◽

Sol Gel ◽

Variable Range Hopping ◽

Electrical Transport Properties ◽

Co Doping ◽

Hopping Model ◽

Variable Range Hopping Model ◽

Co Doped

Microstructures, electrical transport and magnetic properties of Sr[Formula: see text]Ti[Formula: see text]Co[Formula: see text]O[Formula: see text] ceramics are investigated. With Co doping, the Sr[Formula: see text]Ti[Formula: see text]Co[Formula: see text]O[Formula: see text] ceramics remain tetragonal structure while the grain size is decreased with doping. Magnetic moment is enhanced with Co doping and ferromagnetism is observed at low temperatures for Co-doped Sr[Formula: see text]TiO[Formula: see text]. The Sr[Formula: see text]Ti[Formula: see text]Co[Formula: see text]O[Formula: see text] and Sr[Formula: see text]Ti[Formula: see text]Co[Formula: see text]O[Formula: see text] show semiconductor-like transport properties, which can be well fitted by Mott variable range hopping model. The results will provide an effective route to synthesize Sr[Formula: see text]Ti[Formula: see text]Co[Formula: see text]O[Formula: see text] ceramics as well as to investigate the physical properties.

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Oxygen Diffusivity and Defect Transport in Pure and Yb Doped Nano-crystalline Ceria

MRS Proceedings ◽

10.1557/proc-788-l5.3 ◽

2003 ◽

Vol 788 ◽

Author(s):

Laxmikant Saraf ◽

V. Shutthanandan ◽

S. Thevuthasan ◽

C. M. Wang ◽

K. T. Koch ◽

...

Keyword(s):

Grain Size ◽

Electrical Transport ◽

Oxygen Diffusion ◽

Defect Density ◽

Sol Gel ◽

Ionic Transport ◽

Nuclear Reaction Analysis ◽

Electrical Transport Properties ◽

Nano Crystalline ◽

Average Grain Size

ABSTRACTOxygen (18O) diffusivity in sol-gel synthesized nano-crystalline ceria films of average grain size of 3 nm and 7 nm, annealed at 300 °C and 450 °C for one hour respectively is examined by nuclear reaction analysis (NRA). Diffusivity and electrical transport properties measured by a. c. impedance spectroscopy were compared with microcrystalline ceria film of average grain size 38 nm annealed at 900 °C for one hour. Effect of enhanced oxygen diffusion along with reduced ionic transport in nano-crystalline ceria and reduced oxygen diffusion along with enhanced ionic transport in microcrystalline ceria are correlated to long range ordering, grain boundary scattering and defect density. Enhancement in the conductivity with reduction in activation energy from 1 eV to 0.5 eV in the case 4 atom% ytterbium (Yb) doped ceria compared to pure ceria is a result of increased oxygen vacancies taking part in the defect transport.

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Structural and electrical properties of Nd1.7Ba0.3Ni0.9Cr0.1O4+δ compound

Powder Diffraction ◽

10.1017/s0885715612000474 ◽

2012 ◽

Vol 27 (3) ◽

pp. 184-188 ◽

Cited By ~ 3

Author(s):

Manel Jammali ◽

Rached Ben Hassen ◽

Jan Rohlicek

Keyword(s):

Electrical Transport ◽

Small Polaron ◽

Sol Gel ◽

Polycrystalline Sample ◽

Xrd Analysis ◽

Electrical Transport Properties ◽

Polaron Hopping ◽

X Ray ◽

Cell Parameters ◽

Structural And Electrical Properties

The Nd1.7Ba0.3Ni0.9Cr0.1O4+δ polycrystalline sample was synthesized by the sol–gel process and a subsequent annealing at 1523 K in 1 atm of flowing argon. X-ray diffraction (XRD) analysis and electrical transport properties have been investigated as well. The oxygen non-stoichiometry was determined by iodometric titration. The sample shows adoption of the K2NiF4-type structure based on a tolerance factor calculation. Rietveld refinement of the crystal structure from X-ray powder diffraction data confirmed that Nd1.7Ba0.3Ni0.9Cr0.1O4+δ adopts the tetragonal structure (space group I4/mmm, Z = 2). The room temperature unit-cell parameters are determined to be a = 3.82515(2) and c = 12.47528(6) Å. The reliability factors are: RB = 0.043, Rwp = 0.012 and χ2 = 3.00. The Nd1.7Ba0.3Ni0.9Cr0.1O4+δ compound exhibits a semi-conductive behaviour. The electrical transport mechanism has been investigated and it agrees with the adiabatic small polaron hopping model in the temperature range 313 K ≤ T ≤ 708 K.

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SYNTHESIS AND CHARACTERIZATION OF COMPLEX FERROELECTRIC OXIDE

Journal of Advanced Dielectrics ◽

10.1142/s2010135x12500245 ◽

2012 ◽

Vol 02 (04) ◽

pp. 1250024 ◽

Cited By ~ 1

Author(s):

PIYUSH R. DAS ◽

B. N. PARIDA ◽

R. PADHEE ◽

R. N. P. CHOUDHARY

Keyword(s):

Temperature Dependence ◽

Electrical Transport ◽

Room Temperature ◽

Structural Characteristics ◽

Ferroelectric Properties ◽

Complex Impedance ◽

Electrical Transport Properties ◽

Arrhenius Behavior ◽

Orthorhombic Crystal ◽

Grain Distribution

The polycrystalline sample of Li2Pb2Pr2W2Ti4V4O30 was prepared by a solid-state reaction technique. The preparation conditions of the compound have been optimized using thermal analysis (DTA and TGA) technique. Room temperature structural analysis confirms the formation of single phase compound in orthorhombic crystal system. The surface morphology of the sample, recorded by scanning electron microscope, shows uniform grain distribution on the surface of the sample. The observation of hysteresis loop confirmed that the material has ferroelectric properties at room temperature. Electrical properties of the material were studied by complex impedance spectroscopic technique. Temperature dependence of electrical parameters (impedance, modulus, etc.) is strongly correlated to the micro-structural characteristics (bulk, grain boundary, etc.) of the sample. A typical temperature-dependent resistive characteristic of the sample (i.e., negative temperature coefficient of resistance (NTCR)) exhibits its semiconducting properties. The temperature dependence of dc conductivity shows a typical Arrhenius behavior. A signature of ionic conductivity in the system was observed in ac conductivity spectrum. The sample obeys Jonscher's universal power law. The hopping mechanism for electrical transport properties of the system with nonexponential-type conductivity relaxation was suggested from the electrical modulus analysis.

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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.

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