scholarly journals Effect of milling and annealing on microstructural, electrical and magnetic properties of electrodeposited Ni-11.3 Fe-1.4w alloy

2012 ◽  
Vol 44 (2) ◽  
pp. 197-210 ◽  
Author(s):  
M. Spasojevic ◽  
L. Ribic-Zelenovic ◽  
N. Cirovic ◽  
P. Spasojevic ◽  
A. Maricic
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Electrical Resistivity ◽  
Magnetic Permeability ◽  
Structural Relaxation ◽  
Structural Changes ◽  
Xrd Analysis ◽  
Ammonium Citrate ◽  
Maximum Increase ◽  
Electrical And Magnetic Properties

A nanostructured Ni-11.3Fe-1.4W alloy deposit was obtained from an ammonium citrate bath at a current density of 600 mAcm-2. XRD analysis shows that the deposit contains an amorphous matrix having embedded nanocrystals of the FCC phase of the solid solution of Fe and W in Ni with the average crystal grain size of 8.8 nm. The deposit has a high internal microstrain value and a high minimum density of chaotically distributed dislocations. The effect of milling and annealing of the Ni-11.3Fe-1.4W alloy on electrical and magnetic properties was studied. Structural changes in the alloy take place during both annealing and milling. Upon deposition, the alloy was heated to 420?C. Heating resulted in structural relaxation which induced a decrease in electrical resistivity and an increase in magnetic permeability of the alloy. Further heating of the alloy at temperatures higher than 4200C led to crystallization which caused a reduction in both electrical resistivity and magnetic permeability. The milling of the alloy for up to 12 hours caused a certain degree of structural relaxation and crystallization of the alloy. The increase in crystal grain size up to 11 nm and the partial structural relaxation induced a decrease in electrical resistivity and an increase in magnetic permeability of the alloy. Heating the powders obtained by milling at 4200C led to complete structural relaxation, reduced electrical resistivity, and increased magnetic permeability. During heating of the powders obtained by milling at temperatures above 420?C, crystallization and a significant increase in crystal grain size occurred, leading to a reduction in both electrical resistivity and magnetic permeability. The best magnetic properties were exhibited by the alloys milled for 12 hours and annealed thereafter at 420?C. In these alloys, crystal grains were found to have an optimum size, and complete relaxation took place, resulting in a maximum increase in magnetic permeability.

scholarly journals The effect of structural changes during sintering on the electric and magnetic traits of the Ni96.7Mo3.3 alloy nanostructured powder

2009 ◽  
Vol 41 (2) ◽  
pp. 175-184 ◽  
Author(s):  
L. Ribic-Zelenovic ◽  
M. Spasojevic ◽  
A. Maricic ◽  
M.M. Ristic
Keyword(s):  
Electrical Resistivity ◽  
Magnetic Permeability ◽  
Structural Relaxation ◽  
Crystalline Phase ◽  
Structural Changes ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Fcc Lattice ◽  
Lower Permeability ◽  
Structural Powder

Ni96.7Mo3.3 powder was electrochemically obtained. An X-ray diffraction analysis determined that the powder consisted of a 20% amorphous and 80% crystalline phase. The crystalline phase consisted of a nanocrystalline solid nickel and molybdenum solution with a face-centred cubic (FCC) lattice with a high density of chaotically distributed dislocations and high microstrain value. The scanning electronic microscopy (SEM) showed that two particle structures were formed: larger cauliflower-like particles and smaller dendriteshaped ones. The thermal stability of the alloy was examined by differential scanning calorimetry (DSC) and by measuring the temperature dependence of the electrical resistivity and magnetic permeability. Structural powder relaxation was carried out in the temperature range of 450 K to 560 K causing considerable changes in the electrical resistivity and magnetic permeability. Upon structural relaxation, the magnetic permeability of the cooled alloy was about 80% higher than the magnetic permeability of the fresh powder. The crystallisation of the amorphous portion of the powder and crystalline grain increase occurred in the 630 K to 900 K temperature interval. Upon crystallisation of the amorphous phase and crystalline grain increase, the powder had about 50% lower magnetic permeability than the fresh powder and 3.6 times lower permeability than the powder where only structural relaxation took place.

OCCURRENCE OF SUPERCONDUCTIVITY IN Ca-DOPED (Pb,Cu)Sr2PrCu2Oz

2005 ◽  
Vol 19 (01n03) ◽  
pp. 361-367
Author(s):  
H. K. LEE ◽  
Y. H. KIM ◽  
D. H. HA
Keyword(s):  
Magnetic Properties ◽  
Electrical Resistivity ◽  
Structural Changes ◽  
Hole Doping ◽  
Ca Doping ◽  
Bulk Ceramic ◽  
Electrical And Magnetic Properties ◽  
Ceramic Samples ◽  
Doping Effects ◽  
Occurrence Of Superconductivity

We have investigated the Ca -doping effects on the structural, electrical and magnetic properties of ( Pb 0.5 Cu 0.5) Sr 2( Pr 1-x Ca x Cu 2 O z( x =0-0.5) bulk ceramic samples. The electrical resistivity, thermoelectric power and magnetic susceptibility measurements reveal that the Ca doping introduces holes into the system and thereby superconductivity with onset T c, of about 36 K is induced for a phase with x =0.5. These results are discussed in conjunction with the roles of hole doping, structural changes and Pr - O hybridization in CuO 2 layers.

scholarly journals The effect of temperature and frequency on magnetic properties of the Fe81B13Si4C2 amorphous alloy

2011 ◽  
Vol 43 (2) ◽  
pp. 175-182 ◽  
Author(s):  
S. Djukic ◽  
V. Maricic ◽  
A. Kalezic-Glisovic ◽  
L. Ribic-Zelenovic ◽  
S. Randjic ◽  
...  
Keyword(s):  
Signal Processing ◽  
Magnetic Properties ◽  
Amorphous Alloy ◽  
Frequency Domain ◽  
Magnetic Permeability ◽  
Structural Relaxation ◽  
Substantial Reduction ◽  
Effect Of Temperature ◽  
Influence Of Temperature ◽  
Mean Frequency

In this study it was investigated influence of temperature and frequency on permeability, coercivity and power loses of Fe81B13Si4C2 amorphous alloy. Magnetic permeability measurements performed in nonisothermal and isothermal conditions was confirmed that efficient structural relaxation was occurred at temperature of 663 K. This process was performed in two steps, the first one is kinetic and the second one is diffuse. Activation energies of these processes are: Ea1 = 52.02 kJ/mol for kinetic and Ea2 = 106.9 kJ/mol for diffuse. It was shown that after annealing at 663 K coercivity decrease about 30% and therefore substantial reduction in power loses was attained. Investigated amorphous alloy satisfied the criteria for signal processing devices that work in mean frequency domain.

EFFECT OF THICKNESS ON THE STRUCTURAL, MICROSTRUCTURAL, ELECTRICAL AND MAGNETIC PROPERTIES OF Ni FILMS ELABORATED BY PULSED ELECTRODEPOSITION ON Si SUBSTRATE

2018 ◽  
Vol 25 (02) ◽  
pp. 1850058
Author(s):  
T. KACEL ◽  
A. GUITTOUM ◽  
M. HEMMOUS ◽  
E. DIRICAN ◽  
R. M. ÖKSÜZOGLU ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Electrical Resistivity ◽  
Rutherford Backscattering Spectrometry ◽  
Lattice Parameter ◽  
Anisotropy Constant ◽  
Saturation Field ◽  
Grain Sizes ◽  
Electrical And Magnetic Properties ◽  
Effective Anisotropy Constant

We have studied the effect of thickness on the structural, microstructural, electrical and magnetic properties of Ni films electrodeposited onto [Formula: see text]-Si (100) substrates. A series of Ni films have been prepared for different potentials ranging from [Formula: see text]1.6[Formula: see text]V to [Formula: see text]2.6[Formula: see text]V. Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD), four point probe technique, atomic force microscopy (AFM) and vibrating sample magnetometry (VSM) have been used to investigate the physical properties of elaborated Ni thin films. From the analysis of RBS spectra, we have extracted the films thickness [Formula: see text] ([Formula: see text] ranges from 83[Formula: see text]nm to 422[Formula: see text]nm). We found that the Ni thickness, [Formula: see text] (nm), linearly increases with the applied potential. The Ni thin films are polycrystalline and grow with the [Formula: see text] texture. The lattice parameter [Formula: see text] (Å) monotonously decreases with increasing thickness. However, a positive strain was noted indicating that all the samples are subjected to a tensile stress. The mean grain sizes [Formula: see text] (nm) and the strain [Formula: see text] decrease with increasing thickness. The electrical resistivity [Formula: see text] ([Formula: see text]cm) increases with [Formula: see text] for [Formula: see text] less than 328[Formula: see text]nm. The diffusion at the grain boundaries may be the important factor in the electrical resistivity. From AFM images, we have shown that the Ni surface roughness decreases with increasing thickness. The coercive field [Formula: see text], the squareness factor [Formula: see text], the saturation field [Formula: see text] and the effective anisotropy constant [Formula: see text] are investigated as a function of Ni thickness and grain sizes. The correlation between the magnetic and the structural properties is discussed.

scholarly journals Structural, Optical, Electrical, and Magnetic Properties of PVA:Gd3+ and PVA:Ho3+ Polymer Films

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
M. Obula Reddy ◽  
B. Chandra Babu
Keyword(s):  
Electrical Conductivity ◽  
Magnetic Properties ◽  
Polymer Films ◽  
High Mobility ◽  
Magnetic Characteristic ◽  
Xrd Analysis ◽  
Spectroscopy Analysis ◽  
Electrical And Magnetic Properties ◽  
Ferromagnetic Nature ◽  
Solution Casting Method

Polymer films of PVA:Gd3+ and PVA:Ho3+ have been synthesized by a solution casting method in order to study their structural, optical, electrical, and magnetic properties. The semicrystalline nature of the polymer films has been confirmed from XRD analysis. The FTIR analysis confirms the complex formation of the polymer with the metal ions. Dielectric studies of these films have also been carried out at various set temperatures in the frequency from 100 Hz to 1 MHz for carrying out impedance spectroscopy analysis to evaluate the electrical conductivity which arises due to a single conduction mechanism and thus to have a single semicircle pattern from these polymer films. The DC electrical conductivity increases with an increase in the temperature and it could be due to high mobility of free charges (polarons and free ions) at higher temperatures. The conductivity trend follows the Arrhenius equation for PVA:Gd3+ and for PVA:Ho3+ polymer films. PVA:Gd3+ polymer films show ferromagnetic nature, and PVA:Ho3+ polymer films have revealed paramagnetic nature based on the trends noticed in the magnetic characteristic profiles.

Magnetoresistance, temporal evolution, and relaxation of the electrical resistivity in the re-entrant semiconducting La0.80Ba0.20CoO3 perovskite

1999 ◽  
Vol 14 (6) ◽  
pp. 2533-2539 ◽  
Author(s):  
R. D. Sánchez ◽  
J. Mira ◽  
J. Rivas ◽  
M. P. Breijo ◽  
M. A. Señarís-Rodríguez
Keyword(s):  
Magnetic Properties ◽  
Electrical Resistivity ◽  
Temporal Evolution ◽  
The Other ◽  
Inhomogeneous System ◽  
Metal Insulator ◽  
Relaxation Effects ◽  
Electrical And Magnetic Properties ◽  
Semiconducting Behavior ◽  
Insulator Sequence

We report here a study on the electrical and magnetic properties of La1−xBaxCoO3 in the re-entrant semiconducting region (x = 0.20). We find that in this material: (i) the insulator-metal-insulator sequence is unstable and evolves toward a purely semiconducting behavior; the initial r versus T curve can be reinstated upon appropriate annealing treatments; (ii) there are relaxation effects that can be seen by changing the polarity of the electrodes; (iii) there is a negative magnetoresistance Δρ/ρ ∼ 2–3%, for a field as low as 9 kOe, especially at the metal-insulating transition temperatures; and (iv) there are important fluctuations in the electrical resistivity. Taking into account these experimental observations, we can interpret this material as an inhomogeneous system where two thermodynamic phases, one semiconducting and the other metallic and ferromagnetic, coexist, although they are crystallographically indistinguishable.

ON THE STRUCTURAL, THERMAL, ELECTRICAL, AND MAGNETIC PROPERTIES OF AuSn

1963 ◽  
Vol 41 (12) ◽  
pp. 2252-2266 ◽  
Author(s):  
J.-P. Jan ◽  
W. B. Pearson ◽  
A. Kjekshus ◽  
S. B. Woods
Keyword(s):  
Thermal Conductivity ◽  
Magnetic Properties ◽  
Electrical Resistivity ◽  
Magnetic Susceptibility ◽  
Air Temperature ◽  
Homogeneity Range ◽  
Room Temperature ◽  
Lattice Constants ◽  
Conduction Electrons ◽  
Electrical And Magnetic Properties

The Au1−xSn phase has a homogeneity range within the limits 50.0 and 50.5 at.% Sn. The lattice constants and observed densities vary between the limits:[Formula: see text]The thermal conductivity, electrical resistivity, and absolute thermoelectric power of oriented single crystals of Au1−xSn have been measured between 2.5° K and room temperature. The results exhibit pronounced anisotropies. Measurements of the magnetic susceptibility between liquid air temperature and 650–750° K are also reported for three different Au1−xSn alloys.The various results are discussed, and some speculations are presented regarding the number of conduction electrons in AuSn.

Investigation of Structural, Electrical and Magnetic Properties of Mixed Ferrite System

2014 ◽  
Vol 1047 ◽  
pp. 119-122
Author(s):  
Nidhi M. Astik ◽  
G.J. Baldha
Keyword(s):  
Magnetic Properties ◽  
Spinel Structure ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Stoichiometric Mixture ◽  
Ceramic Method ◽  
Oxygen Ions ◽  
Electrical And Magnetic Properties ◽  
Metallic Cations ◽  
Polycrystalline Form

The mineral having chemical compositional formula MgAl2O4 is called “spinel”. The ferrites crystallize in spinel structure are known as spinel-ferrites or ferro-spinels. The spinel structure has an fcc cage of oxygen ions and the metallic cations are distributed among tetrahedral (A) and octahedral (B) interstitial voids (sites). A compound of Co0.85Ca0.15-yMgyFe2O4 (y=0.05, 0.10, 0.15) is synthesized in polycrystalline form, using the stoichiometric mixture of oxides with conventional standard ceramic technique and characterized by X-ray diffraction (XRD).The XRD analysis confirmed the presence of cubic structure. The intensity of each Bragg plane is sensitive to the distribution of cations in the interstitial voids of the spinel lattice. The computer program Powder X software for XRD analysis has been utilized for this purpose. The compositions of Co0.85Ca0.15-yMgyFe2O4 (y=0.05, 0.10, 0.15) ferrites have been prepared by standard ceramic method with double sintering at 950°C, 1100°C. In present study, we report the structural, electrical and magnetic properties of above said compound.

Microstructure and Magnetic Properties of CoFeHfO Rich Nanocrystalline Thin Films Application for High Frequency

2007 ◽  
Vol 558-559 ◽  
pp. 975-978
Author(s):  
L.V. Tho ◽  
K.E. Lee ◽  
Cheol Gi Kim ◽  
Chong Oh Kim ◽  
W.S. Cho
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Magnetic Properties ◽  
Rf Sputtering ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
Electrical And Magnetic Properties ◽  
Transmission Electron ◽  
Nanocrystalline Thin Films

Nanocrystalline CoFeHfO thin films have been fabricated by RF sputtering method. Co52Fe23Hf10O15 thin film is observed, exhibit good magnetic properties with magnetic coercivity (Hc) of 0.18 Oe; anisotropy fild (Hk) of 49 Oe; saturation magnetization (4лMs) of 21 kG, and electrical resistivity (ρ) of 300 01cm. The frequency response of permeability of the film is excellent. The effect of microstructure on the electrical and magnetic properties of thin film was studied using X-ray diffraction (XRD) analysis and conventional transmission electron microscopy (TEM). The results showed that excellent soft magnetic properties were associated with granular nannoscale grains of α-CoFe and α-Co(Fe) phases.

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