الفهرس 
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Abstract
This work had bee done in an attempt to prepare superconductor materials and study its hysico chemical properties. To achieve this
goal, the Bi-Sr-Ca-Cu-O (BSCCO) system has been prepared by solidstate
reaction using Bi J, srCoJ, CaC03 and CuO with different
composition and differe t annealing time. PbO and BaC03 were used
as doped materials to tudy their effects on the superconducting
properties. Different te hniques have been utilized to study the
properties of the prepar materials XRD, TG, surface morphology,
density measurements, oisture effect, dc electrical conductivity
measurements and de agnetic measurements. Also the La2CU04
system has been studied u ing the electrochemical technique.
This thesis is pres ted in five main chapters: introduction,
theories and method of c Iculation, experimental, characterization of
samples, results and disc sion.
The first chapter is th introduction, which includes some aspects
of the origin of the superc nductivity. A literature survey was carried
out to cover, almost, the ast decade related to the proposed subject.
Also it is includes the aim fwork.
The second chapte includes highlight on the theories and the
calculation methods use in this work.
The third chapter sows the preparation of the Bi-Sr-Ca-Cu-O
system with different co position and different annealing time and the
preparation of La2CuO compound. This chapter also includes the
different techniques us in the investigation of the samples (XRDTO
- surface morpholo - density measurements - moisture effect)
and measuring the elect ical and magnetic properties. The preparation
ofLa2Cu04 ring-disk ele trodes has been reported.
The fourth chapter c ntains the samples characterization using the
prior mentioned techniq es (XRJ), TO, surface morphology, density
measurements and mois e effect).
The fifth chapter divi ed into two parts:
Part (A) includes e temperature dependence of the electrical
resistance for all the PI’ pared samples. Also this part contains the
results of magnetic me urements. The results were discussed and
correlated with composi ion-of the samples, and the effect of the
annealing time. Compar ng the obtained results from de electrical
measurements and magn tic measurements with the XRD analysis to
the supercondu ing properties. The effect of doping on the
samples using Pb and Sa has been studied
studying of the dissolution behavior of
La2Cu04 by using electr chemical techniques in aqueous media under
open circuit conditions a 298 K. Rotating ring-disk electrode (RRDE)
techniques were emplo ed in collection (product detection) and
shielding (reactant remo al) measure modes to monitor the surface
chemistry, including a ew approach not involving separate disk
electrode It” reduction measurements as required before. Also
converted the La2CU04 emiconduetor material to a superconductor
material (La2Cu04+x) at room temperature usi.ng a um.que
electrochemical oxidatio method. The electrochemical efficiency of
anodic formation of the uperconductor phase, ”La2CU04+xin, alkaline
medium has been studied
The main conclusions of is work are the following:
1- Thermal analysis sho s that all the samples are thermal stable lip to
1023 K.
2- The XRr> analysis or all the prepared samples indicates the
presence of the two superconducting phases; 2212, 2223 and a
semiconducting phase ; 220 I.
3- A <Jiffi’actionpeak at 5.90 which corresponds to the double Cu-O
layers have been obs ed for all the samples, 2212, this explains
the superconducting
4- The increase in the intensity of 4.80 peak corresponded to the
increase of diamagnet c susceptibility of the high T< phase, which is
clear in sample EMS, oped with Ba.
5- The surface morpho ogy of the samples indicates that all the
samples have the s e type of surface and the addition of Pb2+ or
Ba2+did not change type of crystal formed but causes a change
in the size of crystals it means that they can be used as nucleation
centers for supercond cting phases.
6- The de electrical mea urements showed a metallic behavior for all
the samples from 300 to 120 K.
7- The change in the mposition or the annealing time plays an
important role in the preparation and properties of the
superconductor mate also
8- Using doping substan e as Pband Ba can be enhancement the value,
9- The addition of lead 00.3 atomic ratio increases the T. but more
addition of lead in ces an insulator phase which causes an
increase in the resis ce at temperature above To. This can be
observed from the re istance values at 150 K for the samples
containing lead.
10- All samples at 1123 K were superconducting, with
bulk of their resistanc DROP between 120 and 135 K, however the
Tc,ollv’ aried with the history.
11- The maximum To,o was 73 K in a sample EM2 heated at 1123
K FQr 10 days and slo ly cooled, and the minimum was 52 K in a
sample EM3 heated at 1123 K for 3 days and slowly cooled.
12- The magnetic me urements showed a diamagnetic behavior for
all the samples.
13- The dissolution re ion of La2CU04 with protons is limited by
mass transport.
14- New simplified m thod for determining the number of protons
in the dissolution reac ion can be made.
15- La2CU04 has che ical reaction properties in common with those
QfBa2YCU3O, and is uch more reactive than CuO.
16- The rate of forma .on of superconductor phase is very slow, the
maximum thickness f the superCQnductor formed was about 163
nm thick from short t e experiments.