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SUPERVISOR
Hadi Salamati mashhad,Parviz Kameli
هادی سلامتی مشهد (استاد راهنما) پرویز کاملی (استاد مشاور)
 
STUDENT
Toktam Morshedloo
تکتم مرشدلو

FACULTY - DEPARTMENT

دانشکده فیزیک
DEGREE
Master of Science (MSc)
YEAR
1385

TITLE

The effect of the substitution of Sr by Ba in two series of Bi-2223 superconductors And optimization of Bi-2223/Ag superconducting tapes
This thesis of consists two parts: In the first part, substitution of Ba for Sr i Bi-2223 superconductor and in the second part, fabrication of Bi(Pb)-2223/Ag uperconductor tape by different conditions for finding optimized parameters of prepration process, have been investigated. To investigate the effece of the partial substitution of Sr by Ba in the Bi-2223 superconductor and studying the relation of nominal compoisition of the samples, two series of samples with different nominal compoisition (A) Bi 1.8 Pb 0.4 Sr 2-x Ba x Ca 2.2 Cu 3 O y (x=0, 0.1, 0.2, 0.3) and (B) Bi 1.66 Pb 0.34 Sr 2-x Ba x Ca 2 Cu 3 O y (x=0, 0.1, 0.2, 0.3, 0.4, 0.5) have been preparated by solid-state reaction method. The XRD and SEM analysis and the results of the electrical resistivity and AC susceptibility measurements show that the relative composition of initial elements used in Bi-2223 is essential to the site that is selected by the Ba ions. In A sery, Ba doping up to x=0.1 would improve the phase formation of Bi-2223, and improve the superconductivity properties of the grains and grain boundaries.The flux pining force in the grain boundaries has been improved by small precipitates of Ba-rich phases as point deffects. In B sery, although Ba doping up to x=0.1 would enhance the phase formation of Bi-2223, but it would decrease the coupling between the grain and superconductivity properties of this systems by producing more impure phases. The presence of lower T C phases would begin to appear for x 0.1, in both system. The superconductivity properties and the phase formation of Bi-2223 would decrease as the Ba concentration increases. .
این پایان نامه شامل دو قسمت است. قسمت اول، بررسی اثر جانشینی Ba در مکان Sr، در ساختار و قسمت دوم، ساخت سیم ابررسانا، بر پایه ی ابررسانای CCO و بررسی روش های مختلف ساخت، جهت به دست آوردن پارامترهای بهینه در روش ساخت می باشد. به منظور بررسی اثر جانشینی Ba در مکان Sr، در ساختار و چگونگی وابستگی این جانشینی به استوکیومتری نمونه ی ساخته شده، دو سری نمونه با استوکیومتری های متفاوت و ، به روش واکنش حالت جامد، ساخته شد.

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