ة مجلة إبن الھیثم للعلوم الصرفة و التطبیقی 2012 السنة 25 المجلد 1 العدد Ibn A l-Haitham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 عة السینیة و درجة الحرارة االنتقالیة للمركب شقیاسات اال Bi2Sr2La2Cu3O10+δ المطعم بالكالسیوم الفائق التوصیل محمد عبد النبي ثجیل ابن الھیثم، جامعة بغداد -قسم الفیزیاء ،كلیة التربیة 2011 ایار10: قبل البحث في، 2011 اذار30:استلم البحث في ألخالصھ CaO في خصائص مركب البزموث الفائقة التوصیل بإضافة كمیات مختلفة من التطعیم بالكالسیوم درسنا تأثیر +Bi2Sr2La2-xCaxCu3O10إلى المركب δ.وقد حصلنا على ثالث نماذج هي A (x=0.4) و ، B (x=0.4) و C (x= 0.8) وأظهر تحلیل . لتقلیدیة في ظل الظروف المثلیاتوقد حضرت النماذج بطریقة تفاعل الحالة الصلبة ا ذو تركیب معیني قائم مع ) C(ذو تراكیب رباعیة الشكل بینما االنموذج ) B وA(عینات األشعة السینیة أن النماذج تم قیست ألمقاومیة. للعینات المطعمة بالكالسیوم بالمقارنة مع العینة الخالیة منهcانخفاض في قیمه ثابت الشبیكه ذو ) A(الكهربائیة عند درجات حرارة مختلفة تحت المجاالت المغناطیسیة الصفریة و أظهرت تفسیر البیانات أن العینة ة بأنها أظهرت ) C(عینة بینما ال " معدنیا" أظهرت سلوكا) B(سلوك شبه موصل، و العینة ل ذو درج موصل فائق التوصی .K 85 حرارة التحول عند المقاومة صفر تساوي تحلیالت األشعة السینیة، درجة حرارة التحول ،ألمقاومیه الكهربائیة -:الكلمات ألمفتاحیه ة مجلة إبن الھیثم للعلوم الصرفة و التطبیقی 2012 السنة 25 المجلد 1 العدد Ibn A l-Haitham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 X-ray Data and Transition Temperature Measurements of Ca Doped Bi2Sr2La2Cu3O10 +δ Superconductor M. A. Thejeel Departme nt of Physics, College of Education Ibn-Al-Haithem, Unive rsity of Baghdad Received in : 30 March 2011 ,Accepted in : 10 May 2011 Abstract We st udied the effect of Ca- dop ing on the p rop erties of Bi-based sup erconductors by addin g differ ent amounts of CaO to the Bi2Sr2La2-xCaxCu3O10+δ comp ound. consequently , we obtained three samples A,B and C with x=0.0, 0.4 and 0.8 resp ectively. The usual solid-state reaction method has been app lied under op timum conditions. The x-ray diffraction analy sis showed that the samp les A and B have tetragonal structures conversely the samp le C has an orthorhombic st ructure. In addition XRD analysis show that decreasin g the c-axis lattice constant and thus decreasing the ratio c/a for samples A,B and C resp ectively. The X-ray florescence p roved that the comp ositions of samp les A,B and C with the ratio of Bi:Sr :La(Ca):Cu which were about 2:2:2:3. Resistivity were measured at different temp eratures under zero magnetic f ields and the data were interp reted. Samp le A shows t hat semiconductor behavior, sa mple B showed a metal behavior and sa mple C showed a sup erconductor behaviors with transition temp erature at zero resistance Tc( off set) were 85 K . Ke y words: Resistivit y, t ran sition t emperat ure and x- ray diffract ion an alysis Introduction Sup erconductors Bi-base are very sensitive to sy nthesis conditions. They change from semiconductors t o metal, from metal to sup erconductors, or from sup erconductors at low T c to high Tc sup erconductors without losing their cryst alline structuere(1). The high sensitivity of sup erconductors to p artial replacement by elements have cations higher oxidation st ates and oxy gen content. oxy gen content is due to the app arent ease to which oxy gen can move in and out of the atomic lattice(2,3). Bi2Sr2Ca2Cu3O10+δ (2223) sy st em is st ill difficult t o sy nthesize in its p ure form, the reason is that the formation of the (2223) p hase is a very slow p rocess taking p lace within a very limited temp erature range, moreover, the weak bonding along the c-axis may also contribute to its st ronger p rop ensity to form intergrowt h p roducts(4) . To obtain a high quality 2223 monophase sup erconductor, the basic and significant knowledge needed is about the thermody namic p rocess of the Bi-sy st em (5), the forming mechanisms and the inter relation of the two sup erconducting p hases 2212 and 2223. The nucleation of (2223) can be formed, if additional lay er of p erovskite –like Cu-Ca-O is inserted into t he (2212) matrix. This inserting p rocess can occur under the sintering temp erature through the fluctuation of comp onent and energy (6). In the p resent work, we have successfully to p repare Bi2Sr2La2-xCaxCu3O10+δ bulk p olycryst alline sup erconductor by using solid state reaction p rocess, we analyze the st ructure ة مجلة إبن الھیثم للعلوم الصرفة و التطبیقی 2012 السنة 25 المجلد 1 العدد Ibn A l-Haitham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 and study the electrical prop erties of Ca-doped Bi2Sr2La2Cu3O10+δ sup erconductor sy nthesized at t he optimum conditions. Experimental The Bi2Sr2La2-xCaxCu3O10+δ samples with different Ca (x=0.0, 0.4, 0.8) were prepared by the standard solid state reaction method usin g mixed p owder of BiO, Sr La2O3, CaO and CuO with a purity of 99.99%. The starting materials were carefully mixed and ground in a mortar. The powders were calcined in air at 800°C for 3 hours with several intermittent grindin gs, and furnace cooled. The comp osition of p rep ared samples was checked by the p owder XRF analysis in order to find the actual Bi/Sr/C a/La/Cu ratio .The p owder was p ressed into disc- shap ed p ellets (1.3 cm) in diameter and (0.2-0.3) cm thick, usin g hy draulic p ress under a p ressure of 7 ton/cm 2 .The p ellets were p resintered in air at (855-860) 0 C for (12) hours with a rate of 250 0 C/hr and then cooled to room temperature by same rate of heating.The presintered p ellets were reground, repressed and resintered in the oxy gen (oxy gen rate 0.2 L/min) at the same range of temp erature for further (6) hours and then cooled to (500) C and annealed in oxy gent for (4) hours and then cooled to room temp erature by same rate of h eating. The exess of oxy gen content (δ) as well as measuring the critical temp eratures by the four - p oint technique have b een describ ed elsewher e (7). The X-ray diffractometer was used to confirm the resultant p hase of the samp les. Results and Discussion The variation of resistivity with temp erature of as sy nthesized Bi2Sr2La2-xCaxCu3O10+ δ samples was measured by the st andard four-p robe technique. The normal st ate resistivity of all the samples showed semiconductors or metal behav iors with resp ect to temp erature. The temp erature dep endence of the resistivity (ρ) samp les with different Ca in Bi2Sr2La2- xCaxCu3O10+δ for (x=0.0,0.4,0.8) is shown in f igure (1). It is found from this figure that the behavior of resistivity (ρ) with the temperature for the sample A with x=0.0 is semiconductor behavior, sample B showed a metal b ehavior at x = 0.4, sample C showed a sup erconductor with transition temperature at zero resistance Tc( offse t) were 85 K at x = 0.8. The compositions of the samples were determined by XRF analysis. The x-ray Florescence p att erns of Bi2Sr2La2-xCaxCu3O10+δ sup erconductors are shown in figures (2,3 and 4). The ratio of Bi:Sr :La(Ca):Cu were found to be about 2:2:2:3. Accordin g to the X-ray diffraction data for the samp les consisted of almost p hase-p ure p oly crystalline Bi-2223 p hase. Fig. (5) shows XRD p atterns taken in x=0.0, 0.4, and 0.8, resp ectively. It shows that all our samples are consisted of a major 2223 p hase and very small amounts of secondary p hases such as SrBiO , Sr,La. Cu-Oδ Sr,Ca and CuO. T he comp arison between the relative intensities of XRD p atterns for the samples with Ca = 0, 0.4 and 0.8, with the relative intensity of the same reflections of the samp le with La =0.0 shows that High- Tc p hase reflections of t he free samp le (Ca= 0) h as lower intensity than samp les have Ca . The lattice parameters have been estimated usin g d-valu es and (hkl) reflections of t he observed x- ray diffraction p attern through the software p rogram based on Cohen , s l east square method(8) , the p arameters a, b, c and C/a are shown in table(1). Fi gure (6) shows decreasin g c/a as comp arable with the free samp le, du e to t he subst itution of Ca which has t he ionic r adius Ca +2 (2.23A 0 ) smaller than that of La +3 (2.74A 0 ) which render c-parameter to be sm aller or get deformed. ة مجلة إبن الھیثم للعلوم الصرفة و التطبیقی 2012 السنة 25 المجلد 1 العدد Ibn A l-Haitham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Conclusions In the present study , we have investigated the effect of simu ltaneous dop ing of Ca in La- Oδ lay er of Bi2Sr2 La2-xCaxCu3O10+ δ. The substitution of Ca for La ions y ields further ho les thus t hey will modulate the st ructure by influencing the char ge balance, o xy gen dist ribution and relev ant interactions p rocess between the neighbor ing lay ers will lead to create more holes in the Cu-O lay ers. The transition temp erature of as grown samples is found to be sensitive to the Ca concentrations it has been observed that maximum Tc (85 K) is achieved for Bi2Sr2La1.2Ca0.8Cu3O10.24 . X-ray diffraction(XRD) analysis showed tetragonal st ructure (samples A and B) and an orthorhombic st ructure (samp le C) with decrease of the c-axis latt ice constant for the samples dop ed with calcium as co mpared with this has no calcium content . It was found t hat the change of the Ca concentrations of all our samp les p roduce a change in the C/a and lattice parameters. Re ferences 1- Jasim, K.A. (2005 )Comparison Study of Tc Between the Sup erconducting Compounds Bi2-x(Hg,Pb)xSr2-y BayCa2Cu3O10+δ and Hg1-xPbxSr2-y BayCa2Cu3O8+δ , Ph.D Thesis , University of Baghdad , College of Science , Phy sics Dep . Iraq . 2- Pertanika, J. (2004) .Thennal Diffusivity M easurement of BSCCO Superconducto 135 - 129): 1(12!. Techno& . Using PVDF T ransducerSci) K300 to 85 ( 3- Yutaka, I.; M asasuke, T.; Tsutomu, Y.; M amoru, I. and Koinuma , H. (1989) (Formation of the High-Tc Phase of Bi1-xPbxSr0.90Ca1.10Cu1.50Oy (0≦x≦0.05), Jp n. J. Appl. Phy s. 28: L1518-L1520 4- M izuno M ., Endo H., Tsuchiya J., Kijima N., sumiy ama A., Tomii Y. and M azaki H.,( Cry stal Structure of the High-Tc Phase in the Pb-Bi-Sr-Ca-Cu-O Sy st em) (1989) Jp n. J.Appl. Phy s., .28, pp . L787-L790 ,. 5- Kouji Yamawaki, Sasaki S.,.Tanak a M , Yamauch i H. and Lee S., ( Single-cryst al X-ray st udy of (Hg,Pb)-1223 sup erconductor at low temp erature), (2000) Phy sica C,.338,.67- 71. 6- Chmaissem, Q.; Huang, O.; Capp oni, J.J.; Chaillout, C.; M arezio, M .; Tholence, J.L. and Santoro, A.,( Neutron p owder diffraction st udy of the cry stal st ructure of HgBa2Ca4Cu5O12+δ at room temp erature and at 10 K) (1994) , Phy sica C, 227 , 1-9 .. 7- Jasim K.A. (2009) Synthesis, X-ray data and electrical prop erties measurements of Bi dop ed TlSr2Ca2Cu3O9-δ sup erconductors , Journal of college of education ,university of M ust ansiriy a 84(1): 806-812 8- Ferguson I.F and.Rogerson A.H : A p rogram for the calculation of the intensities of X-ray or neutron p owder reflections, (1984), Comput. Phys. Commun., 32, 95 Table(1): Value s of lattice paramete r a,b, C/a, oxygen content (δ) and Tc for sample s with diffe rent composi tion of Bi 2S r2La2-xCaxCu3O10+ δ X Tc (OF F)(K) δ(o2) a(A 0 ) b(A 0 ) c(A 0 ) C/a 0.0 ------ -------- 5.402 5.421 37.78 6.99 ة مجلة إبن الھیثم للعلوم الصرفة و التطبیقی 2012 السنة 25 المجلد 1 العدد Ibn A l-Haitham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Fi g. (1): The resistivity de pen den ce on Tem pe ratu re for Bi2S r2La2-xC axCu 3O10+ δ at indi cate d values of (Ca) at x =0.00, 0.4 an d 0.8 0.4 ------ -------- 5.414 5.414 37.63 6.95 0.8 85 0.24 5.423 5. 423 37.32 6.80 ة مجلة إبن الھیثم للعلوم الصرفة و التطبیقی 2012 السنة 25 المجلد 1 العدد Ibn A l-Haitham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Fig .(2) :XRF Pat te rn s for th e s am pl e Bi2S r2La2-xCaxCu3O10+ δ fo r x=0.0 ة مجلة إبن الھیثم للعلوم الصرفة و التطبیقی 2012 السنة 25 المجلد 1 العدد Ibn A l-Haitham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Fi g.(3 ): XRF Patte rn s for th e s am pl e Bi2S r2La2-xCaxCu3O10+ δ fo r x=0. 4 ة مجلة إبن الھیثم للعلوم الصرفة و التطبیقی 2012 السنة 25 المجلد 1 العدد Ibn A l-Haitham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Fig.(4): XRF Patterns for the sample Bi2S r2La2-xCaxCu3O10+ δ for x= 0.8 ة مجلة إبن الھیثم للعلوم الصرفة و التطبیقی 2012 السنة 25 المجلد 1 العدد Ibn A l-Haitham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Fig.(5): XRD Patterns for the sample Bi2S r2La2-xCaxCu3O10+ δ for A (x=0.0), B(x=0.4) and C (x=0.8) ة مجلة إبن الھیثم للعلوم الصرفة و التطبیقی 2012 السنة 25 المجلد 1 العدد Ibn A l-Haitham Journal f or Pure and Applied Science No. 1 Vol. 25 Year 2012 Fig.(6): C/a as function of different Ca for Bi2S r2La2-xCaxCu3O10+ δ