scholarly journals Effect of Substitution of Al for Fe on the Magnetic Phase Transition and Initial Permeability of Zn-Co Ferrites

1970 ◽  
Vol 32 (2) ◽  
Author(s):  
AKM Zakaria ◽  
MA Hakim ◽  
MA Asgar
Keyword(s):  
Temperature Dependence ◽  
Room Temperature ◽  
Initial Permeability ◽  
Complex Permeability ◽  
Transition Temperatures ◽  
X Ray Diffraction ◽  
Al Content ◽  
Different Temperatures ◽  
Phase Spinel ◽  
Academy Of Sciences

The spinel oxides Zn0.4Co0.6AlxFe2-xO4 (x=0.0, 0.25, 0.50, 0.75 & 1.0) have been synthesized in the solid state sintering process in air. X-ray diffraction measurements have been carried out in order to check the phase which showed single phase spinel structure for all the samples. Initial permeability, frequency dependence of the complex permeability sintered at different temperatures has been measured on toroidal samples in the frequency range 1-500 KHz at room temperature. Temperature dependence of the complex permeability has been measured from room temperature to 435°C. Transition temperatures (TC) have been estimated from the temperature dependence of the permeability spectra for all the samples. It is found that the values of transition temperatures (TC) and initial permeability (mi) decrease with increasing substitution of Al content in the system. The values of TC obtained from permeability spectra are compared with those obtained from neutron diffraction data and magnetization measurements. doi: 10.3329/jbas.v32i2.2426 Journal of Bangladesh Academy of Sciences Vol.32(2) 2008 201-208

scholarly journals Effect of Mechanical Load on Defects Level in Soft Ferrite Ceramics

2018 ◽  
Vol 186 ◽  
pp. 02010
Author(s):  
A.B. Petrova ◽  
A.V. Malyshev ◽  
A.P. Surzhikov
Keyword(s):  
Temperature Dependence ◽  
Curie Point ◽  
Room Temperature ◽  
Mechanical Load ◽  
Initial Permeability ◽  
Temperature Dependences ◽  
Four Levels ◽  
Magnetic Ring ◽  
Soft Ferrite ◽  
With Screws

The article presents the results of a study of the effect of mechanical load on the temperature dependence of the initial permeability of LiTiZn soft ferrite ceramics. Regimes of mechanical load were created by a steel non-magnetic ring with screws. In this work, four levels of mechanical load were investigated: without load, with 1, 2 and 3 screws. For obtaining temperature dependences and exclude the influence of prehistory on the initial permeability, the samples were heated to a temperature exceeding the Curie point by 50 degrees, after which they slowly cooled to room temperature. The defects level was determined by the ratio of the parameters β / α of the phenomenological expression, which describes the experimental temperature dependences. It is shown that as the mechanical load increases, the defects level of ferrite ceramics increases, and after load removing, it returns to its original level.

Differences and similarities among hypoxanthinium nitrate hydrate structures

2019 ◽  
Vol 75 (8) ◽  
pp. 1036-1044 ◽  
Author(s):  
Małgorzata Katarzyna Cabaj ◽  
Roman Gajda ◽  
Anna Hoser ◽  
Anna Makal ◽  
Paulina Maria Dominiak
Keyword(s):  
Room Temperature ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Acta Cryst ◽  
X Ray ◽  
Nitrate Hydrate ◽  
Different Temperatures ◽  
Lower Temperature ◽  
Low Temperature Phase ◽  
Nitrate Anions

Crystals of hypoxanthinium (6-oxo-1H,7H-purin-9-ium) nitrate hydrates were investigated by means of X-ray diffraction at different temperatures. The data for hypoxanthinium nitrate monohydrate (C5H5N4O+·NO3 −·H2O, Hx1) were collected at 20, 105 and 285 K. The room-temperature phase was reported previously [Schmalle et al. (1990). Acta Cryst. C46, 340–342] and the low-temperature phase has not been investigated yet. The structure underwent a phase transition, which resulted in a change of space group from Pmnb to P21/n at lower temperature and subsequently in nonmerohedral twinning. The structure of hypoxanthinium dinitrate trihydrate (H3O+·C5H5N4O+·2NO3 −·2H2O, Hx2) was determined at 20 and 100 K, and also has not been reported previously. The Hx2 structure consists of two types of layers: the `hypoxanthinium nitrate monohydrate' layers (HX) observed in Hx1 and layers of Zundel complex H3O+·H2O interacting with nitrate anions (OX). The crystal can be considered as a solid solution of two salts, i.e. hypoxanthinium nitrate monohydrate, C5H5N4O+·NO3 −·H2O, and oxonium nitrate monohydrate, H3O+(H2O)·NO3 −.

scholarly journals Compositional Dependence of Structural Properties of Prepared Alloys and Films

2011 ◽  
Vol 2011 ◽  
pp. 1-6
Author(s):  
M. F. A. Alias ◽  
A. A. J. Al-Douri ◽  
E. M. N. Al-Fawadi ◽  
A. A. Alnajjar
Keyword(s):  
Room Temperature ◽  
Thermal Evaporation ◽  
High Accuracy ◽  
Compositional Dependence ◽  
X Ray Diffraction ◽  
Thermal Evaporation Method ◽  
X Ray ◽  
Glass Substrates ◽  
Different Temperatures ◽  
Good Agreement

Results of a study of alloys and films with various Pb content have been reported and discussed. Films of of thickness 1.5 μm have been deposited on glass substrates by flash thermal evaporation method at room temperature, under vacuum at constant deposition rate. These films were annealed under vacuum around 10−6Torr at different temperatures up to 523 K. The composition of the elements in alloys was determined by standard surfaces techniques such as atomic absorption spectroscopy (AAS) and X-ray fluorescence (XRF), and the results were found of high accuracy and in very good agreement with the theoretical values. The structure for alloys and films is determined by using X-ray diffraction. This measurement reveals that the structure is polycrystalline with cubic structure and there are strong peaks at the direction (200) and (111). The effect of heat treatment on the crystalline orientation, relative intensity, and grain size of films is presented.

Structural and Magnetic Properties of Cobalt and Aluminum Co-Doped ZnO Powders

2008 ◽  
Vol 47-50 ◽  
pp. 600-603
Author(s):  
Yan Yan Wei ◽  
Deng Lu Hou ◽  
Rui Bin Zhao ◽  
Zhen Zhen Zhou ◽  
Cong Mian Zhen ◽  
...  
Keyword(s):  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Sol Gel ◽  
Ferromagnetic Behavior ◽  
Infrared Transmission ◽  
X Ray Diffraction ◽  
Al Content ◽  
Infrared Reflection ◽  
Zno Powders ◽  
Ft Ir

A series of Zn0.95-xCo0.05AlxO (x=0, 0.01, 0.02, 0.05, 0.08, 0.10) powders with different percentages of aluminum was fabricated using the sol-gel method. X-ray diffraction (XRD) revealed that the Co ions and Al ions substitute for Zn2+ ions without changing the wurtzite structure. No impurity phases were found. No clusters or precipitates of cobalt or aluminum were found using scanning electron microscope analysis. Fourier transform-infrared reflection (FT-IR) spectrometry was used to examine the infrared transmission properties and revealed that Co ions were incorporated into the lattice as Co2+ substituting for Zn2+. Ferromagnetic behavior in the samples was obtained at room temperature. As the Al content x increased, the room temperature ferromagnetism of the samples was reduced, and when x increased to 0.08, the room temperature ferromagnetism disappeared.

Temperature dependence of the AV3O7 (A = Ca, Sr) structure

2007 ◽  
Vol 63 (6) ◽  
pp. 836-842 ◽  
Author(s):  
Sebastian Prinz ◽  
Karine M. Sparta ◽  
Georg Roth
Keyword(s):  
Single Crystal ◽  
Temperature Dependence ◽  
Crystal Structures ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Groups ◽  
Temperature Ranges ◽  
First Time

The V4+ (spin ½) oxovanadates AV3O7 (A = Ca, Sr) were synthesized and studied by means of single-crystal X-ray diffraction. The room-temperature structures of both compounds are orthorhombic and their respective space groups are Pnma and Pmmn. The previously assumed structure of SrV3O7 has been revised and the temperature dependence of both crystal structures in the temperature ranges 297–100 K and 315–100 K, respectively, is discussed for the first time.

INFLUENCE OF SAMARIUM SUBSTITUTION ON IMPEDANCE DIELECTRIC AND ELECTROMECHANICAL PROPERTIES OF Pb(1-x)K2xNb2O6

2007 ◽  
Vol 21 (06) ◽  
pp. 931-945 ◽  
Author(s):  
K. SAMBASIVA RAO ◽  
P. MURALI KRISHNA ◽  
D. MADHAVA PRASAD ◽  
JOON HYUNG LEE
Keyword(s):  
Impedance Spectroscopy ◽  
Room Temperature ◽  
Single Phase ◽  
Piezoelectric Properties ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
Electromechanical Properties ◽  
X Ray ◽  
Different Temperatures ◽  
Ferroelectric Hysteresis

Ferroelectric, hysteresis, impedance spectroscopy parameters, AC conductivity, and piezoelectric properties in the ceramics of Pb 0.74 K 0.52 Nb 2 O 6 and Pb 0.74 K 0.13 Sm 0.13 Nb 2 O 6 have been studied. X-ray diffraction study reveals single phase with the orthorhombic structure. The samples were characterized for ferroelectric and impedance spectroscopy properties from room temperature to 600°C. Cole–Cole plots (Z″ versus Z′) are drawn at different temperatures. The results obtained are analyzed to understand the conductivity mechanism in both the samples. The piezoelectric constant d33 has been found to be 96 × 10-12 C/N in PKN.

Elaboration of Low Field and Room Temperature Magnetoresistive Sensor of La0.7Sr0.3MnO3 Nanoparticles Synthesized by Sol-Gel Method

2015 ◽  
Vol 771 ◽  
pp. 121-124 ◽  
Author(s):  
Christian Fredy Naa ◽  
Didier Fasquelle ◽  
Manuel Mascot ◽  
Mitra Djamal
Keyword(s):  
Room Temperature ◽  
Sol Gel ◽  
Magnetic Sensors ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Magnetoresistive Sensor ◽  
Low Field ◽  
Ferromagnetic Nature ◽  
Different Temperatures

Low field and room temperature operation range are two critical requirements for magnetic sensors. In this paper, nanoparticles of La0.7Sr0.3MnO3 (LSMO) were elaborated to fulfill these requirements. La0.7Sr0.3MnO3 nanoparticles were synthesized using sol-gel method. The physical properties of LSMO were examined by X-Ray diffraction and Scanning Electron Microscope. The ferromagnetic nature of LSMO samples was confirmed by magnetization measurements. Nanoparticles were pressed in shape of pellets and sintered at different temperatures of 900°C, 1000°C, 1100°C and 1200°C. Magnetoresistive measurements were taken at room temperature with magnetic field (μH) in range ±110 mT. The experimental results show maximum magnetoresistive ratio and sensitivity of 1.3% and 0.023%/mT respectively for sample sintered at 1000°C. Other sensor characteristics namely hysteresis error, response time and noise measurement were also given.

scholarly journals Complex Permeability and Transport Properties of Zn Substituted Cu Ferrites

1970 ◽  
Vol 34 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Kazi Hanium Maria ◽  
Shamima Choudhury ◽  
MA Hakim
Keyword(s):  
Dielectric Constant ◽  
Transport Properties ◽  
Initial Permeability ◽  
Complex Permeability ◽  
Normal Behaviour ◽  
Zn Addition ◽  
Zn Concentration ◽  
Zn Content ◽  
Sem Micrograph ◽  
Academy Of Sciences

Zn doped Cu ferrite of the composition Cu1-xZnxFe2O4 ferrites for x = 0, 0.1, 0.2, 0.3, 0.4, 0.5,0.6 prepared by standard double sintering ceramic technique. SEM micrograph of all the samplesrevealed that the grain sizes decrease gradually with the increase of Zn content and has greatinfluence on the magnetic and transport properties. Permeability is found to increase with increasein Zn content up to x = 0.4 and then slightly decreases with further increase in Zn. The values ofrelative quality factor (RFQ) changes with Zn concentration. Room temperature DC resistivitychanges significantly with Zn addition. The variation of the resistivity versus frequency was studiedand the dielectric constant of the system has a variation quite opposite to that of the AC resistivity.Dielectric constant shows the normal behaviour of the ferrite materials that can be explained by theinterfacial polarization as predicted by Maxwell and Wagner.Key words: Microstructure; Initial permeability; Dielectric constant; DC resistivityDOI: 10.3329/jbas.v34i1.5486Journal of Bangladesh Academy of Sciences, Vol.34, No.1, 1-8, 2010

scholarly journals Polar and non-polar structures of NH4TiOF3

2019 ◽  
Vol 52 (1) ◽  
pp. 23-26
Author(s):  
O. Boytsova ◽  
I. Dovgaliuk ◽  
D. Chernyshov ◽  
A. Eliseev ◽  
P. O'Brien ◽  
...  
Keyword(s):  
Room Temperature ◽  
Phase 1 ◽  
Structural Features ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase ◽  
Starting Compound ◽  
Different Temperatures ◽  
Fourfold Axis

Ammonium oxofluorotitanate, NH4TiOF3, is probably the best known precursor for the synthesis of anatase mesocrystals. Transformation of NH4TiOF3 into TiO2 through thermal decomposition, accompanied by hydrolysis, preserves some structural features of the precursor. Currently, any discussion of the mechanism of this transformation is difficult, as the exact crystal structure of the starting compound is not available and no intermediate structures are known. This article describes the outcome of single-crystal and powder X-ray diffraction studies, revealing the existence of two polymorphs of the parent NH4TiOF3 at different temperatures. A second-order phase transition from the polar Pca21 α phase (1), stable at room temperature, to the Pma2 β phase (2) above ∼433 K has been demonstrated. The direction of the pseudo-fourfold axis in NH4TiOF3 coincides with the orientation of the fourfold axis of anatase mesocrystals, consistent with a topotactical transformation.

scholarly journals Microstructural and Mössbauer Spectroscopy Studies ofMg1-x ZnxFe2O4x=0.5,0.7Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Jinpei Lin ◽  
Yun He ◽  
Qing Lin ◽  
Ruijun Wang ◽  
Henian Chen
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Zinc Concentration ◽  
Magnetic Phase ◽  
Sol Gel ◽  
Paramagnetic Behavior ◽  
Different Temperatures ◽  
Phase Spinel ◽  
Spectroscopy Studies ◽  
Xrd Patterns

Zinc substituted magnesium ferriteMg1-xZnxFe2O4(x=0.5,0.7)powders have been prepared by a sol-gel autocombustion method. XRD patterns show that the specimens withx=0.5and 0.7 exhibit single-phase spinel structure, and more content of Zn in specimens is favorable for the synthesis of pure Mg-Zn ferrites. Room temperature Mössbauer spectra ofMg1-xZnxFe2O4annealed at 800°C display transition from ferrimagnetic behavior to super paramagnetic behavior with increase in zinc concentration. The Mössbauer spectras of Mg0.5Zn0.5Fe2O4annealed at different temperatures display the magnetic phase change of the ferrite particles.

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