Preparation and Structure Properties of LaBa2Cu2O9, LaBa2CaCu3O12 and LaBa2Ca2Cu5O15 Perovskites

Kareem Ali Jasim,Hind Abdulmajeed Mahdi,Rafah Ismael Noori,Marwa Ayad Abdulmajeed 한국재료학회 2023 한국재료학회지 Vol.33 No.9

In this study we examine variations in the structure of perovskite compounds of LaBa2Cu2O9, LaBa2CaCu3O12 and LaBa2Ca2Cu5O15 synthesized using the solid state reaction method. The samples’ compositions were assessed using X-ray fluorescence (XRF) analysis. The La: Ba: Ca: Cu ratios for samples LaBa2Cu2O9, LaBa2CaCu3O12 and LaBa2Ca2Cu5O15 were found by XRF analysis to be around 1:2:0:2, 1:2:1:3, and 1:2:2:5, respectively. The samples’ well-known structures were then analyzed using X-ray diffraction. The three samples largely consist of phases 1202, 1213, and 1225, with a trace quantity of an unknown secondary phase, based on the intensities and locations of the diffraction peaks. According to the measured parameters a, b, and c, every sample has a tetragonal symmetry structure. Each sample’s mass density was observed to alter as the lead oxide content rose. Scanning electron microscope (SEM) images of the three phases revealed that different Ca-O and Cu-O layers can cause different grain sizes, characterized by elongated thin grains, without a preferred orientation.

Partial Substitution of Copper with Nickel for the Superconducting Bismuth Compound and Its Effect on the Physical and Electrical Properties

Kareem Ali Jasim,Riyam Abd Al-Zahra Fadil,Kassim Mahdi Wadi,Auday Hattem Shaban 한국재료학회 2023 한국재료학회지 Vol.33 No.9

This study focuses on how the partial substitution of copper by nickel nanoparticles affects the electrical and structural properties of the Bi2Ba2Ca2Cu2.9Ni0.1O10+δ, Bi2Ba2Ca2Cu2.8Ni0.2O10+δ and Bi2Ba2Ca2Cu2.6Ni0.4O10+δ compounds. Approximate values of crystallization size and crystallization percentage for the three compounds were calculated using the Scherer, modified Scherer, and Williamson-Hall methods. A great similarity was observed in the crystal size values from the Scherer method, 243.442 nm, and the Williamson-Hall method, 243.794 nm for the second sample. At the same time this sample exhibited the highest crystal size value for the three methods. In the examination of electrical properties, the sample with 0.1 partial substitution, Bi2Ba2Ca2Cu2.9Ni0.1O10+δ was determined to be the best with a critical temperature of 100 K and an energy gap of 6.57639 × 10-21 MeV. Using the SEM technique to analyze the structural morphology of the three phases, it was discovered that the size of the granular forms exceeds 25 nm. It was determined that the samples’ shapes alter when nickel concentration rises. The patterns that reveal the distribution of the crystal structure also exhibit clear homogeneity.

Synthesis and Analysis of the Impact of Partial Mercury Replacement with Lead on the Structural and Electrical Properties of the Hg1-xPbxBa2Ca2Cu3O8+δ Superconductor

Kareem Ali Jasim,Chaiar Abdeen Zaynel Saleh,Alyaa Hamid Ali Jassim 한국재료학회 2024 한국재료학회지 Vol.34 No.1

In this investigation, samples of the chemical (Hg1-xPbxBa2Ca1.8Mg0.2Cu3O8+δ) were prepared utilizing a solid-state reaction technique with a range of lead concentrations (x = 0.0, 0.05, 0.10, and 0.20). Specimens were pressed at 8 tons per square centimeter and then prepared at 1,138 K in the furnace. The crystalline structure and surface topography of all samples were examined using X-ray diffraction (XRD) and atomic force microscopy (AFM). X-ray diffraction results showed that all of the prepared samples had a tetragonal crystal structure. Also, the results showed that when lead was partially replaced with mercury, an increase in the lead value impacted the phase ratio, and lattice parameter values. The AFM results likewise showed excellent crystalline consistency and remarkable homogeneity during processing. The electrical resistivity was calculated as a function of temperature, and the results showed that all samples had a contagious behavior, as the resistivity decreased with decreasing temperature. The critical temperature was calculated and found to change, from 102, 96, 107, and 119 K, when increasing the lead values in the samples from 0.0 to 0.05, 0.10, and 0.20, respectively.

Synthesis and Comparative Analysis of Crystallite Size and Lattice Strain of Pb2Ba1.7Sr0.3Ca2Cu3O10+ Superconductor

Maher Abd Ali Hasan,Kareem Ali Jasim,Hussein Ali Jan Miran 한국재료학회 2022 한국재료학회지 Vol.32 No.2

In this article, Pb2Ba1.7Sr0.3Ca2Cu3O10+δ superconductor material was synthesized using conventional solid-state reaction method. X-ray diffraction (XRD) analysis demonstrated one dominant phase 2223 and some impurities in the product powder. The strongest peaks in the XRD pattern were successfully indexed assuming a pseudo-tetragonal cell with lattice constants of a = 3.732, b = 3.733 and c = 14.75 Å for a Pb-Based compound. The crystallite size and lattice strain between the layers of the studied compound were estimated using several methods, namely the Scherrer, Williamson-Hall (W.H), sizestrain plot (SSP) and Halder Wagner (H.W) approach. The values of crystallite size, calculated by Scherrer, W.H, SSP and H.W methods, were 89.4540774, 86.658638, 87.7555823 and 85.470086 Å, respectively. Moreover, the lattice strain values obtained by W.H, SSP and H.W methods were 0.0063240, 0.006325 and 0.006, respectively. It was noted that all crystallite size results are consistent; however, the best method is the size-strain plot because it gave a value of R2 approaching one. Furthermore, degree of crystallites was calculated and found to be 59.003321%. Resistivity analysis suggests zero-resistance, which is typical of superconducting materials at critical temperature. Four-probe technique was utilized to measure the critical temperature at onset Tc(onset), zero resistivity Tc(off set), and transition (width ΔT), corresponding to temperatures of 128 K, 116 K, and 12 K, respectively.

Uses of the Revised Exchange Rate to Maintain Fair Value of Assets under Covid-19 Crisis

Mohammed Hussein Ali,Hayder Basim Kareem,Jasim Idan Barrak 대한산업공학회 2020 Industrial Engineeering & Management Systems Vol.19 No.4

The research aims to identify the effect of using the modified exchange rate in preserving the fair value of the assets, which are the most important economic variables in the Iraqi economy, which are the growth rate of the amount of money in circulation, the value of Iraq’s crude oil exports, the rate of inflation, the rate of growth of the gross domestic product, which expresses the rate of economic growth and the value of spending Government and the value of foreign direct investment in the presence of the COVID-19 crisis. The research found that the effect of the adjusted exchange rate value on both the rate of growth in the amount of money in circulation in Iraq and the growth rate of GDP in Iraq during the period (2004-2018) was not significant, while the significant effect of the value of the adjusted exchange rate on both the value of Iraqi exports Of crude oil in Iraq, the rate of inflation, the value of government spending, the value of foreign investment during the period (2004-2018). The effect of the revised exchange rate was evident in maintaining the fair value of assets in general and in light of the COVID-19 crisis in particular. The research recommended the necessity for the Central Bank of Iraq to use more effective monetary policies that would help increase the impact on the rate of growth of the amount of money in circulation as well as the rate of growth of gross domestic product, the need to work to diversify sources of income in the Iraqi economy and encourage development in all economic sectors and reduce dependence on oil as a main source For income in Iraq, work to develop economic and financial policies that encourage companies and individuals to invest in all non-oil economic sectors, the need to develop monetary policies that can confront emergency situations that may occur, activate the role of crisis management and increase their levels of efficiency.