Electrical Transport Properties of Polycrystalline Chromium Vanadate

1987 ◽  
Vol 42 (6) ◽  
pp. 577-581 ◽  
Author(s):  
Shubha Gupta ◽  
Y. P. Yadava ◽  
R. A. Singh
Keyword(s):  
Transport Properties ◽  
Electrical Transport ◽  
Energy Gap ◽  
Small Polaron ◽  
Charge Carrier Mobility ◽  
Normal Band ◽  
Electrical Transport Properties ◽  
Polaron Hopping ◽  
Intrinsic Nature ◽  
Type Semiconductor

Electrical transport properties of polycrystalline chromium vanadate (CrVO4) have been studied by measuring its a. c. and d.c. electrical conductivities, thermoelectric power and dielectric constant in the temperature range 300-1000 K. CrVO4 is a p-type semiconductor with an energy gap of 3.6 eV. The compound exhibits extrinsic nature up to 750 K and after that its intrinsic nature arises. The activation energy and charge carrier mobility in the temperature ranges 300-750 K and 750- 1000 K show that the conduction in the extrinsic region is due to a small polaron hopping mechanism and in the intrinsic region it is of the normal band type.

Electrical transport properties of single-crystalline Mn–Zn ferrous ferrite

2001 ◽  
Vol 16 (3) ◽  
pp. 774-777 ◽  
Author(s):  
Yong-Chae Chung ◽  
Han-Ill Yoo
Keyword(s):  
Transport Properties ◽  
Thermoelectric Power ◽  
Electrical Transport ◽  
Small Polaron ◽  
Electrical Transport Properties ◽  
Polaron Hopping ◽  
Single Crystalline ◽  
Small Polaron Hopping ◽  
Hopping Model ◽  
Cation Redistribution

Electrical transport properties, electrical conductivity, and thermoelectric power of a single-crystalline Mn0.45Zn0.43Fe2.12O4 were measured as functions of temperature in the range of 25 to 1000 °C. According to the small polaron hopping model, the values of the activation energy for small polaron hopping (EH) were obtained from the conductivity data in three different temperature regions: 0.032 eV for T < TC, 0.12 eV for TC < T < 600 °C, and 0.25 eV for 600 °C < T < 1000 °C. The behavior of conductivity and thermoelectric power data above TC is discussed in connection with cation redistribution.

Structural and Electrical Transport Properties of La0.67Ba0.33Mn1-yTiyO3 Ceramics

2012 ◽  
Vol 501 ◽  
pp. 86-90
Author(s):  
Zainuddin Zalita ◽  
Shaari Abdul Halim
Keyword(s):  
Transport Properties ◽  
Electrical Transport ◽  
Single Phase ◽  
Small Polaron ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Electrical Transport Properties ◽  
Polaron Hopping ◽  
Phase Compound ◽  
Ti Content

The structural and electrical transport properties of La0.67Ba0.33Mn1-yTiyO3 manganite, with y = 0.00, 0.05, 0.10, 0.15, 0.20, 0.40 and 0.60, prepared using the solid state reaction technique have been investigated. The X-ray diffraction spectra of the Ti substituted samples showed the formation of single phase compound with Pm3m cubic structure except for the y = 0.60 sample, which showed La2Ti2O7 phase formation. Lattice parameter increased with Ti content and then decreased at y = 0.60. Resistivity versus temperature study showed that only samples with y = 0.05 and 0.10 exhibited both metallic and semiconductor-like behaviour with the metal-insulator transition temperature, Tp of 167 K and 43 K, respectively. At higher Ti concentration the samples only showed the semiconducting behaviour. At T < Tp the resistivity curves followed the ρ = ρo1 + ρ1T2 relation and for T > Tp, the curves can be fitted with the nearest neighbour hopping (NNH), variable range hopping (VRH) or/and the small polaron hopping (SPH) models.

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

2012 ◽  
Vol 27 (3) ◽  
pp. 184-188 ◽  
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.

Intrinsic Properties of Doped Lanthanum Manganite

1995 ◽  
Vol 401 ◽  
Author(s):  
G. Jeffrey Snyder ◽  
Ron Hiskes ◽  
Steve DiCarolis ◽  
M. R. Beasley ◽  
T. H. Geballe
Keyword(s):  
High Temperature ◽  
Electrical Transport ◽  
Small Polaron ◽  
Intrinsic Property ◽  
Lanthanum Manganite ◽  
Perovskite Manganites ◽  
Itinerant Electron ◽  
Intrinsic Properties ◽  
Electrical Transport Properties ◽  
Polaron Hopping

AbstractAn investigation designed to display the intrinsic properties of perovskite manganites was accomplished by comparing the behavior of bulk samples with that of thin films; the results show the "colossal magneto resistance" at very low temperatures is not an intrinsic property of the thermodynamically stable 1/3 doped material. Epitaxial 1500 Å films of perovskite La0.67Ca0.33MnO3 and La0.67Sr0.33MnO3 were grown by solid source chemical vapor deposition on LaA1O3 and post annealed in oxygen at 950°C. Crystals were prepared by LASER heated pedestal growth. The magnetic and electrical transport properties are essentially the same. Below Tc/2 the intrinsic magnetization decreases as T2 (as can be expected for itinerant electron ferromagnets) while the intrinsic resistivity increases proportional to T2. The constant and T2 coefficients of the resistivity are largely independent of magnetic field and alkaline earth element (Ca, Sr or Ba). We identify three distinct types of negative magnetoresistance. The largest effect is observed near the Curie temperature and is likely to be due to magnetic critical scattering. There is also magnetoresistance associated with the net magnetization of polycrystalline samples. The high temperature (above Tc) resistivity of La0.67Ca0.33MnO3 is consistent with small polaron hopping conductivity with a transition at 750K, while La0.67Sr0.33MnO3 does not exhibit activated conductivity until about 500K, well above Tc. The limiting low and high temperature resistivities may place a limit on the maximum possible magnetoresistance of these materials.

scholarly journals Gold Nanoparticle-Mediated Noncovalent Functionalization of Graphene for Field-Effect Transistor

2021 ◽  
Author(s):  
Dongha Shin ◽  
Hwa Rang Kim ◽  
Byung Hee Hong
Keyword(s):  
Transport Properties ◽  
Gold Nanoparticle ◽  
Electrical Transport ◽  
Field Effect ◽  
High Performance ◽  
Field Effect Transistor ◽  
Electrical Transport Properties ◽  
Noncovalent Functionalization ◽  
Effect Transistor

Since of its first discovery, graphene has attracted much attention because of the unique electrical transport properties that can be applied to high-performance field-effect transistor (FET). However, mounting chemical functionalities...

scholarly journals Pressure-Induced Structural Phase Transition and Metallization in Ga2Se3 up to 40.2 GPa under Non-Hydrostatic and Hydrostatic Environments

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 746
Author(s):  
Meiling Hong ◽  
Lidong Dai ◽  
Haiying Hu ◽  
Xinyu Zhang
Keyword(s):  
Phase Transition ◽  
Electrical Conductivity ◽  
High Pressure ◽  
Phase Transformation ◽  
Transport Properties ◽  
Electrical Transport ◽  
Structural Phase ◽  
Structure Evolution ◽  
Systematic Research ◽  
Electrical Transport Properties

A series of investigations on the structural, vibrational, and electrical transport characterizations for Ga2Se3 were conducted up to 40.2 GPa under different hydrostatic environments by virtue of Raman scattering, electrical conductivity, high-resolution transmission electron microscopy, and atomic force microscopy. Upon compression, Ga2Se3 underwent a phase transformation from the zinc-blende to NaCl-type structure at 10.6 GPa under non-hydrostatic conditions, which was manifested by the disappearance of an A mode and the noticeable discontinuities in the pressure-dependent Raman full width at half maximum (FWHMs) and electrical conductivity. Further increasing the pressure to 18.8 GPa, the semiconductor-to-metal phase transition occurred in Ga2Se3, which was evidenced by the high-pressure variable-temperature electrical conductivity measurements. However, the higher structural transition pressure point of 13.2 GPa was detected for Ga2Se3 under hydrostatic conditions, which was possibly related to the protective influence of the pressure medium. Upon decompression, the phase transformation and metallization were found to be reversible but existed in the large pressure hysteresis effect under different hydrostatic environments. Systematic research on the high-pressure structural and electrical transport properties for Ga2Se3 would be helpful to further explore the crystal structure evolution and electrical transport properties for other A2B3-type compounds.

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