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.

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.

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.

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.

scholarly journals Detail investigation of thermoelectric performance and magnetic properties of Cs-doped Bi2Sr2Co2Oy ceramic materials

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
B. Özçelik ◽  
M. Gürsul ◽  
G. Çetin ◽  
C. Özçelik ◽  
M. A. Torres ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Electrical Resistivity ◽  
Liquid Phase ◽  
Charge Carrier ◽  
Magnetic Hysteresis ◽  
Ceramic Materials ◽  
Charge Carrier Concentration ◽  
The Other ◽  
Paramagnetic Property ◽  
Microstructural Studies

AbstractBi2Sr2−xCsxCo2Oy materials with 0 ≤ x ≤ 0.15, have been fabricated via the classical ceramic technique. XRD results have indicated that undoped and Cs-substituted samples are composed of Bi2Sr2Co2Oy phase as the major one. Microstructural studies have demonstrated the formation of a liquid phase, which allows a drastic grain growth. This factor is responsible for a drastic improvement of relative density, reaching about 95% of the theoretical one for 0.125 Cs content. On the other hand, electrical resistivity has been reduced up to 14 mΩ cm at 650 °C for 0.125 Cs content, around 40% lower than the obtained in undoped samples. As a consequence, Seebeck coefficient has been decreased due to the raise in charge carrier concentration. The highest power factor at 650 °C (0.21 mW/K2 m) has been found for 0.125 Cs substituted sample, about 40% larger than the obtained in undoped samples, and very similar to the notified in single crystals (0.26 mW/K2 m). Magnetisation with respect to temperature results have demonstrated that measured samples have a paramagnetic property above 50 K, except 0.10 Cs. Magnetic hysteresis curves have shown that the slopes and the magnitudes have increased with decreasing temperature.

TRANSPORT AND MAGNETIC PROPERTIES OF Bi BASED MULTIPHASE SUPERCONDUCTORS

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3741-3743 ◽  
Author(s):  
P. Vašek ◽  
I. Janeček
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Electrical Resistivity ◽  
Magnetic Susceptibility ◽  
Volume Fraction ◽  
The Other ◽  
Hall Voltage ◽  
X Ray Diffraction ◽  
X Ray ◽  
Effective Medium Approach

A series of (Bi,Pb)SrCuCaO samples with varying volume fraction of the 2223 phase (determined by X-ray diffraction) has been prepared. Temperature dependence of the resistance, Hall effect and magnetic susceptibility has been measured. Neither susceptibility (both dc and ac) nor electrical resistivity in magnetic field reveal the presence of the low temperature (2212) phase. On the other hand the Hall voltage in the mixed state is very sensitive to the presence of different phases. Obtained results have been discussed within the frame of the effective medium approach and related to the growth mechanism of the 2223 phase.

Structures and Physical Properties of Ternary Antimonides RE3MSb5 (M = Zr, Hf), U3MSb5 (M = Zr, Hf, Nb), and YbCrSb3

2004 ◽  
Vol 848 ◽  
Author(s):  
Andriy V. Tkachuk ◽  
Shane J. Crerar ◽  
Xing Wu ◽  
Craig P. T. Muirhead ◽  
Laura Deakin ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Electrical Resistivity ◽  
Magnetic Susceptibility ◽  
Rare Earth ◽  
Magnetic Ordering ◽  
Exchange Interactions ◽  
Electronic Transitions ◽  
Magnetic Exchange ◽  
Electrical And Magnetic Properties ◽  
Fertile Ground

ABSTRACTTernary rare-earth transition-metal antimonides RExMySbz have provided fertile ground for discovering materials with varied electrical and magnetic properties such as superconductivity and ferromagnetism. The properties of two important classes of these compounds, RE3TiSb5 and RECrSb3, have been previously investigated. These studies have now been extended to RE3MSb5 (M = Zr, Hf), which show anomalies in their resistivity curves suggestive of electronic transitions, and YbCrSb3, which undergoes long-range magnetic ordering at 285 K, the highest Tc observed so far of all RECrSb3 members. Strong magnetic exchange interactions develop through coupling of f and d electrons in these compounds. The substitution of uranium for rare earth in RE3MSb5 results in the compounds U3MSb5 (M = Zr, Hf, Nb), which also display prominent transitions in their electrical resistivity and magnetic susceptibility curves.

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.

Superconductivity in Fluorine-Arsenide Sr1-xNdxFeAsF

2011 ◽  
Vol 170 ◽  
pp. 87-91 ◽  
Author(s):  
Ryosuke Suganuma ◽  
Tadataka Watanabe ◽  
Kouichi Takase ◽  
Yoshiki Takano
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Room Temperature ◽  
Weak Ferromagnetism ◽  
The Other ◽  
Superconducting Transition ◽  
Metallic Conductivity ◽  
Electrical And Magnetic Properties ◽  
New Family ◽  
Fe Impurity

We have successfully prepared the new family of fluoride-arsenide Sr1-xNdxFeAsF (0 ≤ x ≤ 0.5), and investigated the electrical and magnetic properties. Sr1-xNdxFeAsF with x = 0.4 and 0.5 show superconductivity, and their superconducting transition temperatures are 32 and 49 K, respectively. The superconducting volume fractions of Sr0.6Nd0.4FeAsF and Sr0.5Nd0.5FeAsF are ~11 and ~ 17 %, respectively. On the other hand, the sample of Sr1-xNdxFeAsF (0 ≤ x ≤ 0.35) is not superconducting but shows a metallic conductivity. All compounds show a weak ferromagnetism with the Curie temperature of above room temperature. The origin of the ferromagnetism may be due to the tiny Fe impurity.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

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