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Synthesis and Characterization of Nanoparticles Added Cutl-Based Superconductors

Thesis Info

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Author

Jabbar, Abdul

Program

PhD

Institute

International Islamic University

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2016

Thesis Completion Status

Completed

Subject

Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/2785/1/Abdul_Jabbar_Physics_IIU_2016_10.02.2016.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727455314

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Low anisotropic (Cu 0.5 Tl 0.5 )Ba 2 Ca 2 Cu 3 O 10-δ (CuTl-1223) phase of Cu 1-x Tl x Ba 2 Ca 2 Cu 3 O 10- δ [CuTl-12(n-1)n]; n=1, 2, 3, ... high temperature superconducting (HTSC) family was synthesized by solid-state reaction method. Nanoparticles (NPs) were prepared separately by different techniques (i.e. co-precipitation, sol-gel, and colloidal solution methods). Different kinds and sizes of NPs such as non-magnetic metallic (Ag, Au), non-magnetic metallic oxide (Al 2 O 3 ) and magnetic ferrite (CoFe 2 O 4 ) were added with different wt.% during the final sintering process of CuTl-1223 superconducting matrix to get the required (NPs) x /CuTl-1223 nanoparticles-superconducting composites. These composites were characterized by different experimental techniques such as x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive x-ray (EDX) spectroscopy, resistivity versus temperature measurements, critical current density (J c ) measurements, magnetic ac-susceptibility measurements, Fourier transform infrared (FTIR) spectroscopy etc. The experimental data were analyzed by different well established theoretical models such as Aslamazov-Larkin (AL), Lawerence-Doniach (LD) and Maki-Thompson (MT) models. It was observed that tetragonal structure and stoichiometry of the host CuTl-1223 superconducting phase remained unaltered after the addition of these NPs, which indicates about the occupancy of these NPs at the inter-granular spaces. Non-magnetic metallic NPs (Ag, Au) have improved the superconducting transport properties (T c , J c , etc) up to certain optimum concentration of these NPs in CuTl-1223 matrix. The improvement in the superconducting properties can be attributed to an increase in the inter-grains connectivity by healing up the inter-grains voids and pores after the addition of these NPs. The improved inter-grains connections can facilitate the carriers transport processes across the inter-crystallite sites due to their metallic nature. But the superconducting volume fraction starts to be decreased after certain optimum inclusion level of these non-magnetic non-superconducting metallic NPs, which causes the suppression of superconductivity parameters. The effects of highly coercive cobalt ferrite (CoFe 2 O 4 ) nanoparticles addition on superconducting properties of CuTl-1223 matrix were also explored. The magnetic behavior of CoFe 2 O 4 nanoparticles was determined by MH-loops with the help of superconducting quantum interference device (SQUID). The resistivity versus temperature measurements showed an increase in T c (0), which could be most probably due to improvement of weak-links by the addition of these nanoparticles. The increase of mass density with xxviincreasing content of these NPs can also be an evidence of filling up the voids in the matrix. But the addition of these NPs beyond an optimum level caused the agglomeration and produced additional stresses in material and suppressed the superconductivity. We observed non- monotonic variation of superconducting properties after the inclusion of nano-Al 2 O 3 particles, which can be associated with inhomogeneous distribution of these NPs at the grain-boundaries in CuTl-1223 matrix. But overall suppression of superconducting properties was attributed to a pair-breaking mechanism caused by reflection/scattering of carriers across these insulating nano- Al 2 O 3 particles present at the grain-boundaries of the host CuTl-1223 matrix. The presence of Al 2 O 3 nanoparticles at the grain-boundaries possibly reduced the number of flux pinning centers, which were present in the form of weak-links in pure CuTl-1223 superconducting matrix. The suppression of activation energy {U (eV)} may be due to weak flux pinning in the nano-Al 2 O 3 particles added samples. The superconducting microscopic parameters (i.e. zero temperature coherence length along c-axis {xc (0)}, inter-layer coupling (J), inter-grain coupling (a) etc.) deduced from fluctuation induced conductivity (FIC) analysis with the help of above mentioned theoretical models explained the experimental findings very well. For example, the increase in the values of inter-grain coupling (a) deduced from FIC analysis is a theoretical evidence of improved inter-grain coupling in the host CuTl-1223 matrix with the increased contents of these nanoparticles. We also calculated the activation energy {U (eV)} of (NPs) x /CuTl-1223 nanoparticles-superconducting composites. The increase in T c (0), J c , U (eV) etc and decrease in normal state resistivity {ρ 300 K (Ω-cm)} were observed after the addition Ag, Au and CoFe 2 O 4 NPs in CuTl-1223 superconducting phase. The suppression of superconducting properties (i.e. T c (0), J c , U (eV) etc) after the addition of Al 2 O 3 nanoparticles in host CuTl-1233 superconducting matrix was observed.
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باب چہارم: معدنی وسائل کا مطالعہ

معدنیات کی اہمیت و افادیت

تعارف(Introduction)

معدنی کا لفظ معدن سے ماخوذ ہے۔ فیروز اللغات میں معدن کے لغوی معنی درج ذیل ہیں:

"کان-کھان- وہ جگہ زمین کھود کر دھاتیں۔ کوئلہ وغیرہ نکالیں۔ (جمع) معادن۔ "[1]

معدنیات کے لغوی معنی "وہ چیزیں جو کان سے نکلیں۔ دھات۔ فلّزات۔ "[2] ہیں۔

معدنیات کو اہم قدرتی وسیلہ کہا جاتا ہے۔ پاکستان معدنیا ت سے مالا مال ملک ہے اس لئے وطن عزیز میں معدنیا ت کے امور طے کرنے کے لئے معدنیات کی وزارت قائم کی گئی ہے۔ معدنیات میں سونا، چاندی، لوہا، تانبا اور نمک وغیرہ شامل ہیں۔ معدنیات کے ذخائر کسی بھی ملک کی ترقی و خوشحالی میں انتہائی مثبت کردار ادا کرتے ہیں۔ مسلم ممالک میں معدنی ذخائر کی بھرمار ہے لیکن ملت اسلامیہ کا المیہ یہ ہے کہ یہ ممالک جدید سائنس و ٹیکنالوجی میں مغربی ممالک کے ہم پلہ نہ ہونے کےباعث اپنے معدنی ذخائر کے اخراج کے لئے ان کے زیر تسلط ہیں۔ جدید ٹیکنالوجی سے لیس ہونا ملت اسلامیہ کے لئے ایک چیلنج کی حیثیت رکھتا ہے۔

علم معدنیات (Mineralogy)

انسائیکلوپیڈیا آف بریٹانیکا میں علم معدنیات کی تعریف یوں بیان کی گئی ہے:

“Mineralogy: scientific discipline that is concerned with all aspects of minerals , including their physical properties , chemical composition, internal crystal structure , occurrence and distribution in nature , and their origins in terms of the physicochemical conditions of formation.”[3]

علم معدنیات سے مراد ایسا سائنسی علم ہے جس میں معدنیات کے بارے میں تمام پہلوؤں کا مطالعہ کیا جاتا ہے۔ اس میں معدنیات کےطبعی خواص، کیمیائی ساخت، اندرونی کرسٹل ڈھانچہ کی تشکیل وغیرہ کا احاطہ کیا جاتا ہے۔

انسائیکلوپیڈیڈک ڈکشنری آف...

قیام امن کے لئے حضرت عمر فاروق ؓکی خدمات

Peace has great importance both for the individual and the communal life. Wherever peace turned into unrest, the tendencies of social violence, mental sickness and insecurity start developing amongst the people. Peace and harmony were the hallmark of the reign of the 2nd caliph, Haḍrat ‘Umar. He gave the best governing mechanism to the people of Arab, when they were not fully aware of rules & regulation of government. Though the empire was wide spread, he exercised a great sort of command & control on it. He took the responsibility of providing his subjects their basic needs: Food, Shelter, Education, Peace and Justice. This was not only an ideal system of its time but became the role model for the modern welfare state. Peace and harmony is as important for a state as food & air are for life. Allāh has strongly emphasized in The Holy Qur’ān" on two things i. E., "Disharmony & hunger" which should be eliminated from a society. Haḍrat ‘Umer during his reign of 10 years presented Islām as a religion of peace & harmony, a religion, which respects humanity, peacefully resolves disagreements and curtails misuse of power. He himself possessed the qualities of peace & harmony to an utmost level, which were the traits of our Holy Prophet’s (ﷺ) personality. It is important to follow the Khilāphah of Haḍrat ‘Umar to bring peace & justice in the society.

Pcr Based Genetic Diversity in Kajli Sheep Breed in Punjab, Pakistan Using Mitochondrial Dna Cytochrome-B

Main focus is to study the three districts of Punjab as well as the nearby areas where Kajli breed exists. In this study Kajli breed of sheep from Sargodha, Khushab and Mianwali districts were used. Blood samples of 30 animals up to 5 ml were collected in tubes containing EDTA as anticoagulant. These samples were stored at 4?C. DNA from these blood samples were collected with phenol chloroform extraction method. DNA quality and quantity were tested by 1% agarose gel. Purification of DNA using the liquid/solid-phase approach can be traced back to 1979, when Vogelstein and Gillespie used silica in a glass powder form in their protocol to purify DNA fragments previously separated by agarose gel electrophoresis. These techniques absorb DNA under particular pH and salt content conditions through any of the following principles: 1) Hydrogen binding in the presence of a Chaotropic agent to a hydrophilic matrix, 2) Ionic exchange using an anion exchanger under aqueous conditions 3) Affinity and size exclusion mechanisms. The genomic DNA was extracted from the blood sample and were visualized and confirmed on 1% agarose gel. DNA content was similar in all samples represent that all breeds had similar genome. Position of band in similar region showed that all the breads belong to similar origin. Populations of Mianwali, Khushab and Sargodha regions are clustered into one group. The cluster patterns were concordant with their geographic localities and were also in agreement with our previous studies using microsatellite markers. Amino acid content was also analyzed from the blood samples to determine either there is any difference among sheep belonging to different areas. Majority of amino acids of different breads are similar with each other which showed that their origin is similar from Urial. However, alanine content in sheep located from Sargodha was higher than those located with other areas. Further, valine and isoleucine content of breed from Mianwali was higher than those located in other areas. It is concluded from the analysis that all breeds of Kajli sheep are similar. They might have similar origin from Urial and spread all over the Pakistan. The minute difference in these breeds is due to different kind of breeding that is done in different areas of Pakistan. In the areas of Noorpoor thal and Quaidabad random mating is common while interbreeding is done in various ways in different regions of Mianwali which cause slightly difference in the phenotype of the Kajli sheep.