EFFECT OF Ni ON THE ELECTRICAL AND MICROSTRUCTURAL PROPERTIES OF NANOCRYSTALLITES Fe2O3/TiO2 SYSTEM

2006 ◽  
Vol 13 (04) ◽  
pp. 479-484 ◽  
Author(s):  
MAGED S. SOBHY
Keyword(s):  
Electrical Resistivity ◽  
Spinel Ferrite ◽  
Average Crystalline Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Average Value ◽  
Semiconductor Behavior ◽  
Ion Substitution ◽  
Diffraction Patterns ◽  
Increasing Temperature

Nominal compositions of Ni x Ti 1-x Fe 2 O 5-δ (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) were prepared by a solid state reaction using stoichiometric amounts of Fe 2 O 3/ TiO 2 system and NiO as a dopant. The effects of small substitution of Ni ions on the electrical and structural properties were studied for the above system. The X-ray diffraction patterns revealed that the ferroelectric phase of iron titanate and the spinel ferrite phase of Ni -ferrite having a single phase at x = 0 and 1, respectively. The substitution of Ni ions increases the average value of lattice constant aav. Solid–solid interaction took place between the ternary oxides at 1200°C for 4 h yielding a new phase of NiTiO 3. The presence of the three phases was confirmed by X-ray diffraction technique. The resultant compositions have nanocrystallites with average crystalline size "D av " in the range 100–300 nm. The DC electrical resistivity ρ, Curie temperature TC and activation energies for electric conduction around TC region increase as Ni ion substitution increases. The ferrite samples have a semiconductor behavior where electrical resistivity ρ decreases on increasing temperature. The activation energy for electrical conduction was affected by both the ratio "ferroelectric/ferrite" and the position of the Curie temperatures in the compositions depending on the ( Ni , Ti ) to Fe ratio.

scholarly journals AgSn[Bi1−xSbx]Se3: Synthesis, Structural Characterization, and Electrical Behavior

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 864
Author(s):  
Paulina Valencia-Gálvez ◽  
Daniela Delgado ◽  
María Luisa López ◽  
Inmaculada Álvarez-Serrano ◽  
Silvana Moris ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Seebeck Coefficient ◽  
X Ray ◽  
Average Value ◽  
Transmission Electron ◽  
Semiconductor Behavior ◽  
Type Semiconductor ◽  
Diffraction Patterns ◽  
Increasing Temperature ◽  
P Type

Herein, we report the synthesis, characterization, and electrical properties of lead-free AgSnm[Bi1−xSbx]Se2+m (m = 1, 2) selenides. Powder X-ray diffraction patterns and Rietveld refinement data revealed that these selenides consisted of phases related to NaCl-type crystal structure. The microstructures and morphologies of the selenides were investigated by backscattered scanning electron microscopy, energy-dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy. The studied AgSnm[Bi1−xSbx]Se2+m systems exhibited typical p-type semiconductor behavior with a carrier concentration of approximately ~+1020 cm−3. The electrical conductivity of AgSnm[Bi1−xSbx]Se2+m decreased from ~3.0 to ~10−3 S·cm−1 at room temperature (RT) with an increase in m from 1 to 2, and the Seebeck coefficient increased almost linearly with increasing temperature. Furthermore, the Seebeck coefficient of AgSn[Bi1−xSbx]Se3 increased from ~+36 to +50 μV·K−1 with increasing Sb content (x) at RT, while its average value determined for AgSn2[Bi1−xSbx]Se4 was approximately ~+4.5 μV·K−1.

Ferromagnetic properties and Nanocrystallization behavior of Amorphous (Fe0.99Mo0.01)78Si9B13 Ribbons

2001 ◽  
Vol 674 ◽  
Author(s):  
Xiang-Cheng Sun ◽  
J. A. Toledo ◽  
S. Galindo ◽  
W. S. Sun
Keyword(s):  
Amorphous Phase ◽  
Magnetic Ordering ◽  
Metastable Phases ◽  
X Ray Diffraction ◽  
Ferromagnetic Properties ◽  
X Ray ◽  
Diffraction Patterns ◽  
Optimum Annealing Temperature ◽  
Increasing Temperature ◽  
Differential Scanning Calorimeters

ABSTRACTFerromagnetic properties and nanocrystallization process of soft ferromagnetic (Fe0.99Mo0.01)78Si9B13 ribbons are studied by transmission electron microscope (TEM), X-ray diffraction (XRD), Mössbauer spectroscopy (MS), differential scanning calorimeters (DSC) and magnetization measurements. The Curie and crystallization temperature are determined to be TC=665K and Tx = 750K, respectively. The Tx value is in well agreement with DSC measurement results. X-ray diffraction patterns had shown a good reconfirm of two metastable phases (Fe23B6, Fe3B) were formed under in-situ nanocrystallization process. Of which these metastable phases embedded in the amorphous matrix have a significant effect on magnetic ordering. The ultimate nanocrystalline phases of α-Fe (Mo, Si) and Fe2B at optimum annealing temperature had been observed respectively. It is notable that the magnetization of the amorphous phase decreases more rapidly with increasing temperature than those of nanocrystalline ferromagnetism, suggesting the presence of the distribution of exchange interaction in the amorphous phase or high metalloid contents.

Electrical and Magnetoelectric Properties of (Y)Li0.5Ni0.7Zn0.05Fe2O4 + (1-Y)Ba0.5Sr0.5TiO3 Magnetoelectric Composites

2014 ◽  
Vol 592-594 ◽  
pp. 826-830 ◽  
Author(s):  
S.U. Durgadsimi ◽  
S.S. Chougule ◽  
S.S. Bellad
Keyword(s):  
Dielectric Behavior ◽  
Dc Resistivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Magnetoelectric Composites ◽  
Voltage Coefficient ◽  
Magnetoelectric Properties ◽  
Semiconductor Behavior ◽  
Tan Δ ◽  
Increasing Temperature

(y) Li0.5Ni0.7Zn0.05Fe2O4+ (1-y) Ba0.5Sr0.5TiO3magnetoelectric composites with y = 0.1, 0.3 and 0.5 were prepared by a conventional standard double sintering ceramic technique. X-ray diffraction analysis confirmed the phase formation of ferrite, ferroelectric and their composites. logρdcVs 1/T graphs reveal that the dc resistivity decreases with increasing temperature exhibiting semiconductor behavior. The plots of logσacVs logω2are almost linear indicating that the conductivity increases with increase in frequency i.e. conductivity in the composites is due to small poloron hopping. Dielectric constant (έ) and dielectric loss (tan δ) were studied as a function of frequency in the range 100Hz–1MHz which reveal the normal dielectric behavior except the composite with y = 0.1and as a function of temperature at four fixed frequencies (i.e. 100Hz, 1KHz, 10KHz, 100KHz). ME voltage coefficient decreases with increase in ferrite content and was observed to be maximum of about 7.495 mV/cmOe for S1i.e. (0.1) Li0.5Ni0.7Zn0.05Fe2O4+ (0.9) Ba0.5Sr0.5TiO3composite.

Enhancement of thermoelectric power factor in CrSi2 film via Si:B addition

2015 ◽  
Vol 29 (27) ◽  
pp. 1550189
Author(s):  
Q. R. Hou ◽  
B. F. Gu ◽  
Y. B. Chen
Keyword(s):  
Electrical Resistivity ◽  
Thermoelectric Power ◽  
Raman Spectra ◽  
Power Factor ◽  
Low Temperatures ◽  
X Ray Diffraction ◽  
Thermoelectric Power Factor ◽  
X Ray ◽  
Large Enhancement ◽  
Diffraction Patterns

In this paper, we report a large enhancement in the thermoelectric power factor in CrSi2 film via Si:B (1 at.% B content) addition. The Si:B-enriched CrSi2 films are prepared by co-sputtering CrSi2 and heavily B-doped Si targets. Both X-ray diffraction patterns and Raman spectra confirm the formation of the crystalline phase CrSi2. Raman spectra also indicate the crystallization of the added Si:B. With the addition of Si:B, the electrical resistivity [Formula: see text] decreases especially at low temperatures while the Seebeck coefficient [Formula: see text] increases above 533 K. As a result, the thermoelectric power factor, [Formula: see text], is greatly enhanced and can reach [Formula: see text] at 583 K, which is much larger than that of the pure CrSi2 film.

scholarly journals Structure, magnetic and magnetic transport properties of layered cobaltite Sr0.9Y0.1CoO2.63

2018 ◽  
Vol 62 (5) ◽  
pp. 555-562
Author(s):  
M. О. Troyanchuk ◽  
M. V. Bushinsky
Keyword(s):  
Monoclinic Phase ◽  
Spontaneous Magnetization ◽  
Magnetic Moments ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Magnetic Transport ◽  
Diffraction Patterns ◽  
Increasing Temperature

The structure, magnetic and magnetotransport properties of perovskite Sr0.9Y0.1CoO2.63are studied. It is shown that the sample is structurally two-phase. The main phase has a tetragonal-distorted unit cell and is described by the spatial group I4/mmm. The broadening of the reflexes with indexes corresponding to a doubling of the parameter from the unit cell indicates that there is no strict translational symmetry along the с-axis. The presence of a broadened superstructural reflex observed at small angles on X-ray diffraction patterns at temperatures below 400 K is due to the monoclinic phase, whose content is much smaller than the tetragonal phase. Spontaneous magnetization appears during the formation of the monoclinic phase. The magnetic structure is predominantly an antiferromagnetic G-type structure with magnetic moments of 1.5µBin the layers of CoO6octahedra and 2µBin the anion-deficient CoO4+γlayers. The electrical conductivity of Sr0.9Y0.1CoO2.63has a semiconductor in character. The magnetoresistance reaches 57 % in a field of 14 T at a temperature of 5 K and decreases strongly with increasing temperature.

Structural and magnetic variations in Ba0.5Sr0.5Fe9Ce1Al2O19 hexaferrites at different sintering temperatures

2021 ◽  
Author(s):  
A.R. Makhdoom ◽  
Qasim Ali Ranjha ◽  
Ubaid-ur-Rehman Ghori ◽  
Muhammad Ahsan Raza ◽  
Binish Raza ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Recording Media ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Structural Variations ◽  
X Ray ◽  
Pure Phase ◽  
Different Temperatures ◽  
Diffraction Patterns ◽  
Increasing Temperature

Abstract M-type hexaferrites has attracted researchers due to their ordinary magnetic properties and utilization as media for magnetic recording and microwave devices. In this study we have synthesized Ba0.5Sr0.5Fe9Ce1Al2O19 via conventional ceramic route. The synthesized material is treated against different temperatures and investigated structurally and magnetically by using several techniques such as X-ray diffraction, Scanning electron microscopy, and VSM respectively. Morphology of samples confirms the absence of secondary phases and uniform distribution of particles. X-ray diffraction patterns confirms the formation of pure phase of Hexaferrites. Microstructural analyses show the decrease in porosity and dislocations among sintered samples. Magnetic properties for the samples show a decrease in Ms and Mr with increasing temperature from 1225 °C to 1310 °C, while coercivity shows an increase with increasing temperature and maximum coercivity is observed at 1290 °C. The trends and occurrences can be well-linked to the structural variations and sintering effects. The results suggest that material can be used in various magnetic applications such as Recording media, and memory devices.

EFFECT OF γ RADIATION ON SOME PHYSICAL PROPERTIES OF THE SPINEL FERRITE SYSTEM Ni0.65Zn0.35CuxFe2−xO4

1994 ◽  
Vol 08 (28) ◽  
pp. 1781-1790 ◽  
Author(s):  
F.S. TERRA
Keyword(s):  
Electrical Resistivity ◽  
Room Temperature ◽  
Spinel Ferrite ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Γ Radiation ◽  
X Ray ◽  
Resistivity Measurements ◽  
Dta Analysis ◽  
Ferrite System

X-ray diffraction analysis, electrical resistivity measurements at room temperature, and differential thermal analysis (DTA) were carried out for γ-irradiated Ni 0.65 Zn 0.35 Cu xFe2−x O 4 spinel ferrite samples. It was found that the lattice parameter decreased, i.e. the theoretical density increased, while the electrical resistivity decreased. From the DTA analysis there is an endothermic peak at 100–130º C due to internal stress created by γ radiations as a result of lattice defects formation.

Influence of Temperature on the Order-Disorder Transition in Gd2Zr2O7

2016 ◽  
Vol 697 ◽  
pp. 386-389 ◽  
Author(s):  
Jing Lin Shi ◽  
Zhi Xue Qu ◽  
Qun Wang
Keyword(s):  
Fluorite Structure ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Inconsistent Result ◽  
Disorder Transition ◽  
X Ray ◽  
Influence Of Temperature On ◽  
Diffraction Patterns ◽  
Co Precipitation ◽  
Increasing Temperature

Chemical co-precipitation method was used to prepare Gd2Zr2O7 powders. The powders were then heated in air at 1500°C, 1510°C, 1525°C, 1530°C, 1550°C, 1575°C, 1600°C for 5 h, and 1575°C, 1600°C for 10 h, respectively. The samples after heat treatment were characterized by X-ray diffraction and Raman spectroscopy. X-ray diffraction patterns reveal that order-disorder transition of Gd2Zr2O7 occurs between 1550°C and 1575°C. Prior to the transition, the relative intensity of peaks corresponding to the super-lattice of pyrochlores increases with the increasing temperature. On the other hand, Raman spectra give an inconsistent result from the X-ray diffraction data. No appreciable difference can be observed for all the samples though with peaks broadening as temperature increases. The spectra of the samples indicated as fluorite structure in X-ray diffraction patterns appear with six resolvable peaks which is quite different from the spectrum of ideal fluorite structure.

X-Ray Diffraction Studies of Structural Dimensionality in Carbon Fibers

1982 ◽  
Vol 20 ◽  
Author(s):  
James Stamatoff ◽  
Harris Goldberg ◽  
Ilmar Kalnin
Keyword(s):  
Carbon Fibers ◽  
Structural Transition ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Turbostratic Carbon ◽  
Structural Dimensionality ◽  
Diffraction Patterns ◽  
Increasing Temperature

ABSTRACTDiffraction patterns of carbon fibers have been recorded photographically using monochromatized MoKα radiation. <001> and <hk0> reflections are observed for fibers pyrolyzed at lower temperatures. The absence of <hkl> reflections suggests that the graphite planes are turbostratic. A three-dimensional structural transition is manifest in the appearance of <hkl> reflections. The results suggest that the degree of three dimensionality increases progressively through the sample as a function of increasing temperature of pyrolysis. There is no evidence for coexistence of three dimensional and tubostratic phases. It is further demonstrated that turbostratic carbon fibers may be intercalated to stage two with AsF5.

Influence of Annealing Temperature on the Properties of Zn-Sb Composite Thin Films by Magnetron Sputtering

2015 ◽  
Vol 1096 ◽  
pp. 76-79
Author(s):  
Yu Huan Sun ◽  
Juan Qin ◽  
Guo Hua Wang ◽  
Wei Min Shi
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
X Ray Diffraction ◽  
Composite Thin Films ◽  
X Ray ◽  
Hall Measurements ◽  
Different Temperatures ◽  
Diffraction Patterns ◽  
Increasing Temperature ◽  
P Type

Zn-Sb based composite thin films have been prepared by radio frequency magnetron sputtering using a Zn4Sb3 compound target followed by thermal annealing. Sample structure and surface morphology were analyzed by X-ray diffraction (XRD) and atomic force microscopy (AFM). The electrical properties of the films were studied by Hall measurements. The X-ray diffraction patterns reveal that the intensity of diffraction peak of ZnSb phase is enhanced as temperature increasing. Results of AFM shows the rms roughness is getting big with increasing temperature due to the growing crystal grains. Hall measurements indicate that the Zn-Sb composite thin films annealed at different temperatures are p-type conducting with carrier concentrations being on the order of 1019 cm-3.

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