The partial substitution of copper with nickel oxide on the Structural and electrical properties of HgBa2 Ca2 Cu3xNix O8+δ superconducting compound

In this paper the structural and electrical evolution of Au/Ni contacts to p-type gallium nitride (GaN) upon annealing in different atmospheres was monitored. Rapid annealing of the contacts in an oxidizing atmosphere (N2/O2) resulted into a lower specific contact resistance (ρc) with respect to annealing in non-reacting ambient (Ar). The formation of a nickel oxide (NiO) layer was observed on the surface of the sample annealed in N2/O2 ,while was not present at the interface with p-GaN. The improvement of the contacts was associated with a reduction of the Schottky barrier height from 1.07 eV (Ar annealing) to 0.71 eV (N2/O2 annealing), as determined by the temperature dependence of the ρc. Local electrical measurements demonstrated the formation of inhomogeneous barriers. The electrical measurements were correlated with the different microstructure of the annealed contacts.

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Synthesis of HgSr2-xYxCa2Cu3O8+ δ Superconducting Compound

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.886.42 ◽

2021 ◽

Vol 886 ◽

pp. 42-47

Author(s):

Mustafa K. Kamil ◽

Maher A. Hasan ◽

Kareem Ali Jasim ◽

Auday H. Shaban

Keyword(s):

High Temperature ◽

Critical Temperature ◽

Electrical Resistance ◽

Partial Substitution ◽

Special Focus ◽

X Ray Diffraction ◽

X Ray ◽

Structural And Electrical Properties ◽

Superconducting Compound ◽

Yttrium Concentration

The superconductivity phenomenon and the method of preparing the superconductingmercury-based (HgSr2-xYxCa2Cu3O8+δ with x=0 to 0.15) compound were presented in this paper. The physical properties of the compound are presented at a high temperature, with a special focus on the effect of partial substitution of strontium with Yttrium (Y). The effect on structural and electrical properties were investigated. All the samples in the present investigation were subjected to gross structural characterization by X-ray diffraction. The XRD data collected from various have the Hg1223 phase and the analysis showed that all samples correspond to the tetragonal structure. The electrical resistance uses the four probe technology to find the critical temperature and found that it drops from 116 K to 81K by increase the yttrium concentration.

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Partial substitution Effect of Pb and Mg on the Structural and Electrical Properties of High Temperature (Hg1-xPbxBa2Ca3-yMgyCu4O10+δ) Superconductor

Tikrit Journal of Pure Science ◽

10.25130/j.v24i2.804 ◽

2019 ◽

Vol 24 (2) ◽

pp. 68

Author(s):

Shaheen S. Aldin Alimardan1 ◽

Abdul Kareem D. Ali2 ◽

Sabah J. Fathi1

Keyword(s):

Electrical Properties ◽

Substitution Effect ◽

Solid State Reaction Method ◽

Partial Substitution ◽

X Ray Diffraction ◽

Homogeneous Surface ◽

Force Microscopy ◽

Atomic Force ◽

Tetragonal Crystal ◽

Structural And Electrical Properties

superconductor samples with chemical composition (Hg1-xPbxBa2Ca3-yMgyCu O10+δ) were prepared by solid state reaction method. The effect of partial substitution of Pb and Mg on the structural and electrical properties of this compound were studied. The lattice parameters were characterized by using X-ray diffraction technique and the results showed that all the samples crystallize in tetragonal crystal structure. This technique proved increase in value of lattice constant (c) with increasing in Pb concentration until 0.4 when y= 0 and decreased after this concentration. On the other hand the partial substitution of Mg in Ca showed decreasing in the value of (c) with increasing Mg concentration to (0.2,0.4,0.8,1,1.4,1.6) when the Pb is constant at (0.4), but the value of (c) increased with increasing Mg to (0.6,1.2). Standard four-probe method used in electrical resistivity measurements and the measurements showed an improvement in Tc from (0.1-0.4) and after this concentration Tc value decreased at substitution of Pb in Hg when Mg=0, where the critical temperature increases from 121K to 134K with an increase of x from 0 to 0.4 and decreases after this concentration to 120K , but for substitution of Mg in Ca the Tc is increased to 135K,136K,139K,142K and 145K with increasing of Mg to (0.2,0.4,0.8,1,1.4) and decreased to 134K,140K and 140K with increasing concentration of Mg to (0.6,1.2,1.6) while Pb is constant at (0.4). The surface has been investigated by using scanning electron microscope (SEM) and atomic force microscopy (AFM). These tests were shown that all specimens which tested have good crystalline and homogeneous surface . http://dx.doi.org/10.25130/tjps.24.2019.034

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