【摘要】 本文研究了不同退火温度对Y₁Ba₂Cu₃O_y块体材料形成的影响.通过XRD,SEM表征方法检查了Y₁Ba₂Cu₃O_y相的形成和微结构特点.从XRD图谱可以得到在860℃到930℃热处理温度下,都能形成正交相的Y-123.观察柠檬酸盐热分解法制备和固相反应法制备的Y₁Ba₂Cu₃O_y的SEM照片,柠檬酸盐热分解法制备样品晶粒尺寸远远小于固相反应法制备样品,并且随着热处理温度的升高,晶粒尺寸有所增加,孔洞数减小.随后测量了样品的R-T曲线.对于880℃,910℃,880℃热处理12h的样品,在正常态具有很好的金属性,Tc,onset,Tc,zero最高.柠檬酸盐热分解法制备样品的R-T曲线的转变宽度与固相反应法制备样品的曲线相近.最后,通过拉曼光谱检查880℃,910℃,900℃,热处理条件下样品,O（4）-Ag峰的位移在502.7cm^-1,表明样品良好的正交结构和超导特性.更多还原

【Abstract】 The effects of different annealing temperature on Y₁Ba₂Cu₃O_y（Y-123）bulk superconducting materials fabricated by citrate pyrolysis technique are studied.The phase formation and microstructure of Y₁Ba₂Cu₃O_y bulk material are systematically investigated through XRD,SEM.The XRD patterns of Y-123 shows the annealing temperature from 860℃ to 930℃,the crystal structure of Y-123 is orthorhombic structure.Observing the morphology of the fractured core layers of Y-123 sample by SEM,it can be found that the sample prepared by citrate pyrolysis technique has smaller grain size and hole size than the sample fabicated by the solid phase reaction and with the increasing of annealing temperature,the number of holes decreases but the grain size increases.Subsequently,the R-Tcurves of samples with different annealing temperature are measured.The sample processed 12 hat 880℃,910℃,880℃for each time has the best metallic behavior on normal statea and Tc,onset,Tc,zeroare the highest.The transition width of the sample fabricated by citrate pyrolysis technique is close to the sample prepared by solid phase reaction method.At last,from the Raman spectrum of sample processed 12 hat 880℃,910℃,880℃ for each time,the Raman shift of O（4）-Agpeak of the sample is 502.7cm^-1,which indicates that the sample has a well orthorhombic structure and good superconductivity.更多还原