Critical Magnetic Field of (Bi1.7Pb0.3)Sr-Ca-Cu-O and (Bi1.6Pb0.4)-Sr-Ca-Cu-O
superconducting ceramics

Supreya Trivijitkasem and Adisak Boonchun
Department of Physic ,Faculty of Science,Kasetsart University,Bangkok 10900,Thailand


     AC susceptibility as a function of temperature T and applied field amplitude H of (Bi1.7Pb0.3)-Sr-Ca-Cu-O and (Bi1.6Pb0.4)-Sr-Ca-Cu-O superconducting samples were studied. The samples of nominal composition 2234 were prepared by solid reaction without or with an intermediate ground and pressed. High critical field of the bulk samples and low critical field (grain and matrix) could be utilized from the complex susceptibility measurements. As T?TC(critical temperature), low critical field of matrix Hc1m calculated from Clem’s model were consistent with experimental data. London penetration depth and coherence length were reported. The critical current density (grain and matrix) were employed from Bean medel.

 

Fig. 1 for sample Bi1.7Pb0.3Sr2Ca3Cu4O (N), the ac applied field amplitude are a,b,c,d,e,f,g,h = 0.1, 1, 10, 100, 200, 300, 400 and 500 A/m, respectively.