scholarly journals Structural and electrical properties of Ti doped α-Fe2O3

2013 ◽  
Vol 45 (3) ◽  
pp. 281-292 ◽  
Author(s):  
M.V. Nikolic ◽  
D.L. Sekulic ◽  
N. Nikolic ◽  
M.P. Slankamenac ◽  
O.S. Aleksic ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Grain Boundary ◽  
Relaxation Process ◽  
Equivalent Circuit ◽  
Impedance Analysis ◽  
Eds Analysis ◽  
Structural And Electrical Properties ◽  
Ti Doping ◽  
Boundary Contribution

In this work we have analyzed the effects of Ti doping on structural and electrical properties of ?-Fe2O3. When the amount of added Ti (5 wt.%TiO2) was within the solubility degree and XRD, SEM and EDS analysis revealed a homogenous hematite structure, with lattice parameters a= 5.03719(3) ?, c=13.7484(1) ? slightly increased due to incorporation of Ti into the rhombohedral hematite lattice. Higher amounts of Ti (10 wt.%TiO2) resulted in the formation of pseudobrookite, besides hematite, confirmed by SEM and EDS analysis. Studies of electric properties in the temperature range 25-225oC at different frequencies (100 - 1Mz) showed that Ti doping improved electrical conductivity. Impedance analysis was performed using an equivalent circuit, showing one relaxation process and suggesting dominant grain boundary contribution.

Effect of TiO2 Nanoparticle on the Structural and Electrical Properties of Nd0.67Sr0.33MnO3 /TiO2 Composites

2021 ◽  
Vol 317 ◽  
pp. 60-65
Author(s):  
Kean Pah Lim ◽  
Lik Nguong Lau ◽  
Amirah Natasha Ishak ◽  
Mohd Mustafa Awang Kechik ◽  
Soo Kien Chen ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Grain Boundary ◽  
Double Exchange ◽  
Secondary Phase ◽  
Solid State Reaction Method ◽  
Peak Shift ◽  
Boundary Region ◽  
Structural And Electrical Properties ◽  
Xrd Patterns ◽  
Grain Surface

In this work, (1-x) (Nd0.67Sr0.33MnO3): x (TiO2) composites with x = 0, 0.1, 0.2, 0.3 and 0.4 have been prepared to investigate the structural and electrical properties. Nd0.67Sr0.33MnO3 (NSMO) was synthesised via the solid-state reaction method before incorporated with TiO2. The addition of TiO2 nanoparticle as the secondary phase in manganite composite would favour the spin-polarized tunnelling near to the grain boundary and thus enhance the extrinsic magnetoresistance. Nevertheless, nanoparticle addition might contribute to substitution and diffusion with manganite compound as reported in literature. The effect of the TiO2 nanoparticle addition into NSMO composites has been examined by an X-ray diffractometer (XRD) and a four-point probe (4PP) system. From the thermogravimetric analysis (TGA), NSMO phase formation occurred in between 756.45 - 977.59 °C. XRD patterns showed that there is no peak shift when the TiO2 concentration increases. It can be deduced that TiO2 was segregated at the NSMO grain boundary region and its grain surface. However, a small amount of Ti atoms are expected to replace the Mn atoms in NSMO crystal system and has caused the increase in crystallite size. The electrical study showed that the presence of TiO2 nanoparticle and substitution of Ti in Mn sites have weaken the double exchange (DE) mechanism and suppressed the metal-insulator transition temperature (TMI). In addition, the insulating behaviour of TiO2 has also caused the resistivity of composites to increase drastically.

Method of High Active Preparation and Electrical Properties of CuFeO2 Delafossite-Type

2014 ◽  
Vol 979 ◽  
pp. 302-306 ◽  
Author(s):  
Chalermpol Rudradawong ◽  
Aree Wichainchai ◽  
Aparporn Sakulkalavek ◽  
Yuttana Hongaromkid ◽  
Chesta Ruttanapun
Keyword(s):  
Crystal Structure ◽  
Electrical Conductivity ◽  
Solid State ◽  
Electrical Properties ◽  
Grain Boundary ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Lattice Parameter ◽  
Metal Powders ◽  
High Power Factor

In this paper, the CuFeO2compound were prepared by classical solid state reaction (CSSR) and direct powder dissolved solution (DPDS) method from starting material metal oxides and metal powders. Preparation of two methods shows that, direct powder dissolved solution faster recover phases than classical solid state reaction method. The fastest method gets from starting materials Cu and Fe metal powders, the electrical conductivity, Seebeck coefficient, carrier concentration and mobility are 10.68 S/cm, 244.59 μV/K, 12.86×1016cm-3and 494.96 cm2/V.s, respectively. In addition, each CuFeO2compounds were investigated on crystal structure and electrical properties. From XRD and SEM results, all samples have a crystal structure delafossite-typeand a large grain boundary more than 15 μm by electrical conductivity corresponds to grain boundary and lattice parameter: a increases. Within this paper, from above results exhibit that preparation CuFeO2from Cu and Fe by direct powder dissolved solution method most appropriate for thermoelectric oxide materials due to high active for preparation else high lattice strain and high power factor are 0.00052 and 0.64×10-4W/mK2, respectively.

Non-Stoichiometry and Structure of SrCe1-xYbxO3 Perovskite-Type Oxides

1996 ◽  
Vol 453 ◽  
Author(s):  
Igor Kosacki ◽  
Mark Shumsky ◽  
Harlan U. Anderson
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Charge Carrier ◽  
Structural Properties ◽  
Electrical Transport ◽  
Structural Disorder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural And Electrical Properties ◽  
Perovskite Type

AbstractThe structural and electrical properties of SrCe1-xYbxO3 ceramics have been studied as a function of temperature and Yb-concentration using x-ray diffraction and impedance techniques. The influence of Yb-dopants on electrical transport and structural disorder has been studied. A correlation between the structural properties, electrical conductivity is observed and discussed. These measurements allow us to determine the mechanism of charge carrier compensation and also the concentration and mobility of the electrical species.

The Electrical Properties and Impedance Analysis of ZnO Varistors Doped with Different Cu2O Contents

2014 ◽  
Vol 681 ◽  
pp. 173-176
Author(s):  
Ji Wei Fan ◽  
Hui Jun Zhao ◽  
Xiao Li Zhang
Keyword(s):  
Electrical Properties ◽  
Grain Boundary ◽  
Leakage Current ◽  
Impedance Analysis ◽  
Boundary Resistance ◽  
Zno Varistors ◽  
Good Agreement

The Cu2O addition deteriorates the electrical properties of ZnO varistors, which is a good agreement with similar findings on Ag2O additions. The best fitted impedance analysis reveals that the Cu2O addition increases grain resistance and lowers the grain boundary resistance, results in low nonlinearity and higher leakage current of ZnO varistors.

scholarly journals The Effect of Fe and Mn Substitution on Structural and Electrical Properties of LaCoO3 Nanoparticles

2019 ◽  
Vol 8 (6) ◽  
pp. 3213-3217
Keyword(s):  
Chemical Composition ◽  
Electrical Properties ◽  
Sol Gel ◽  
Impedance Analysis ◽  
Structure And Morphology ◽  
Edax Analysis ◽  
Structural And Electrical Properties ◽  
Fe And Mn ◽  
Mn Substitution ◽  
Mn Doped

Pure and Fe, Mn doped LaCoO3 nanoparticles are primed by sol gel ignition method, and their electrical properties are studied. All the materials were characterized to study the structure and morphology. The chemical composition of the samples was analysed by EDAX analysis revealing that La, Co, O (Mn, Fe) compounds were present. Electrical properties were identified in impedance analysis and the conductivity of the materials was calculated. And it is found that Fe doped LaCoO3 possesses higher conductivity than all others

Synthesis and Thermoelectric Properties of WO3/Cu2SnSe3 Composites

2018 ◽  
Vol 913 ◽  
pp. 811-817 ◽  
Author(s):  
Di Wu ◽  
Ji Ai Ning ◽  
De Gang Zhao ◽  
Xue Zhen Wang ◽  
Na Liu
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Grain Boundary ◽  
Figure Of Merit ◽  
Milling Process ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Plasma Sintering ◽  
Spark Plasma

In this study, nanometer WO3 powder was uniformly dispersed into the Cu2SnSe3 powder by ball milling process, and the WO3/Cu2SnSe3 thermoelectric composite was prepared by spark plasma sintering (SPS). The results showed that the nano-WO3 particles were mainly distributed in the grain boundary of Cu2SnSe3 matrix, and the grain growth of Cu2SnSe3 was inhibited. The addition of nano-WO3 could enhance the electrical conductivity of Cu2SnSe3, and while the Seebeck coefficient increased slightly for the 0.4% WO3/Cu2SnSe3 composite. The thermal conductivity was not decreased until the content of WO3 exceeded 1.6%. The highest thermoelectric figure of merit ZT of 0.177 was achieved at 700 K for 0.4% WO3/Cu2SnSe3 composite. The enhancement of ZT value of WO3/Cu2SnSe3 thermoelectric material was mainly attributed to the improvement of the electrical properties.

scholarly journals Grain boundary effects on piezoelectric properties of the core–shell-structured BaTiO3@TiO2 ceramics

2018 ◽  
Vol 08 (06) ◽  
pp. 1850044 ◽  
Author(s):  
Xixi Li ◽  
Zhonghua Yao ◽  
Juan Xie ◽  
Zongxin Li ◽  
Hua Hao ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Grain Boundary ◽  
Boundary Effect ◽  
Ferroelectric Properties ◽  
Critical Role ◽  
Impedance Analysis ◽  
Ferroelectric Materials ◽  
Boundary Effects ◽  
Grain Boundary Effects ◽  
Grain Boundary Effect

Grain boundary effect on BaTiO3 has been widely investigated for several decades. However, all of them tailored the grain boundary by grain size of BaTiO3. In this case, a direct way was introduced to modify the grain boundary by coating technique to investigate the role of grain boundary in ferroelectric materials. Nonferroelectric phase TiO2 was employed to investigate grain boundary effects on the electrical properties of BaTiO3 piezoelectric ceramics. TiO2 coating can result in the reduction of piezoelectric and ferroelectric properties and the annealing process in oxygen can increase piezoelectric behavior of pure BaTiO3 due to valence state of Ti ions while that remains for Ti-modified composition possibly due to the increased grain boundary effect by impedance analysis. Compared with ferroelectric grain, grain boundary plays a critical role to impact the electrical properties of perovskite-type ferroelectric materials.

New Fabrication (PVA-CMC -PbO) Nanocomposites Structural and Electrical Properties

2021 ◽  
Vol 19 (4) ◽  
pp. 38-46
Author(s):  
Manar S. Toman ◽  
Sameer Hassan Al-nesrawy
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Electrical Properties ◽  
Dielectric Loss ◽  
Electric Field ◽  
Lead Oxide ◽  
Optical Microscope ◽  
Structural And Electrical Properties ◽  
Oxide Concentration ◽  
Structural Aspects

This paper presents the work conducted on preparing (PbO PVA-PEG) nanocomposites through adding the different weight concentrations of lead oxide (0,1,3,5,7 wt%). The structural aspects such as optical microscope, FTIR and electrical features of nanocomposites (PVA-CMC/PbO) were examined. The resulting data shows that the dielectric constant decreased along with the decline of dielectric loss, whereas the frequency value rose while applying of an electric field. As for the electrical conductivity AC, the dielectric loss and dielectric constant of all samples rose along with the increase in lead oxide concentration.

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