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Superconductive Ceramic
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ABSTRACT

Since the discovery of superconductivity in mercury in 1911 by kamerlingh Onnes superconductivity was found in many other metals and in an extremely large number of metallic alloys and compounds . The highest temperature of the transition to the superconducting state ( critical temperature T_c ) increased in steps whit year as shown in Figure 8.1.1 and had reached 23 K for Nb₃ Ge by 1973 . stable cooling to achieve  superconductivity for these so-called conven tional metallic superconductors is possible only by using liquid helium (4.2K) which makes the technology complex and costly . As a result superconductivity application was limited to special ones such as the generation of strong magnetic field which could not be attained by using conventional copper wire. In early 1986 Bednorz and Mueller made the amazing and unexpected discovery of high-temperature superconductivity at around 35K in La-Ba-Ca-Cu-O system .