Твердофазним методом синтезовано серію зразків ВТНП кераміки складу (Pb1-уCuу)Sr2(Y1-хCaх)Cu2O7-б9, (Pb1212) 0[додається формула] x [додається формула] 0,3). Досліджено залежність параметрів кристалічної гратки системи від ступеня заміщення х. Резистивні вимірювання зразків даної системи в інтервалі температур 77-300 К показали, що надпровідний перехід при температурі вище 77 К не спостерігається.
Твердофазным методом синтезирована серия образцов ВТСП керамики состава Pb1-уCuу)Sr2(Y1-хCaх)Cu2O7-б9, (Pb1212) 0[дается формула] x [дается формула] 0,3). Исследована зависимость параметров кристаллической решетки системы от степени замещения х. Резистивные измерения образцов данной системы в интервале температур 77-300 К показали, что сверхпроводящий переход при температуре выше 77 К не наблюдается.
Polycrystalline samples of (Pb1-уCuу)Sr2(Y1-хCaх)Cu2O7-б9, (Pb1212) 0 [add formulas] x[add formulas] 0,3) were prepared to study the influence of Pb/Bi substitution on its physical properties. Ceramic HTSC samples of (Pb1-уCuу)Sr2(Y1-хCaх)Cu2O7-b9, (Pb1212) 0 [add formulas] x [add formulas] 0,3) were synthesized by standart solid-state reaction from the starting materials Bi2O3, PbO, SrCO3, Y2O3, CaCO3 and CuO. In the first stage a mixture of powders take&n in stoichiometric ratio calculated carefully grinded in the agate mortar and annealed in porcelain crucibles in a muffle furnace for 48 hours at 900°C in the disappearance of the characteristic absorption bands of CO3 2_- in IR spectra ( with inter&mediate grinding ). After that the powder was properly mixed in agate mortars and pressed into pellets. The pellets were sintered for 72 hour at temperatures 850-900°C in air. A second annealing was performed at 750°C in flowing O2 for 8 h. The X-Ray& diffraction patterns reveals that all the compounds are crystallized in space group P4/mmm R123 structure and show mainly the formation of the tetragonal Pb1212 phase. Dependence of lattice parameters from the displacement degree x was studied. Chan&ge of lattice parameters related to a possible transition Pb2+/Pb4+. It"s adjusted that for solid solutions (Pb1-уCuу)Sr2(Y1-хCaх)Cu2O7-b9, (Pb1212) 0 [add formulas] x[add formulas] 0,3) have superconductivity properties in temperature interval bello&w 77-300 K. Our study reveals that superconductivity and structure stabilization in Pbbased are more critical to sintering conditions that other cuprates. The SEM images of the objects under investigation show particles of different shape which have &diameter 1 ?m. Therefore, findings suggest that with increasing degree of substitution x an increase in the volume of the unit cell is shown that one of the main factors that affect the crystallographic features of this system is the ratio of cations& Pb: Cu: Bi.
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