A Review on Cuprate Based Superconducting Materials

Abstract

Sumit Kumar Gupta

When Bednorz and Müller discovered the superconductivity in a compound La-Ba-Cu-O in 1986, it was considered as a breakthrough in the research of the superconductivity. This leads to the discovery of the other cuprate superconductors, and immediately the transition temperature of the synthesized materials reached to the liquid nitrogen temperature. Today the maximum transition temperature of the cuprate superconductors changes from 35 K for La2 −xSrx CuO4 to 138 K for Hg1−xTlx Ba2 Ca2 Cu3 Oy (the highest record under normal pressure, which extends to ∼160K at high pressure). High-temperature superconductivity in the Non-stoichiometric cuprate lanthanum barium copper oxide . The Tc for this material was 35 K, well above the previous record of 23K. Thousands of publications examine the superconductivity in cuprates between 1986 and 2001, and Bednorz and Müller were awarded the Nobel Prize in Physics only a year after their discovery. From 1986 to 2008, many cuprate superconductors were identified, the most famous being yttrium barium copper oxide (YBa2 Cu3 O7 , "YBCO" or "1-2-3"). Another example is bismuth strontium calcium copper oxide (BSCCO or Bi2 Sr2 Can Cun+1O2n+6-d ) with Tc = 95–107 K depending on the n value. Thallium barium calcium copper oxide (TBCCO, TlmBa2 Can−1Cun O2n+m+2+δ ) was the next class of high-Tc cuprate superconductors with Tc = 127 K observed in Tl2 Ba2 Ca2 Cu3 O10 (TBCCO-2223) in 1988. The highest confirmed, ambient-pressure, Tc is 135 K, achieved in 1993 with the layered cuprate HgBa2 Ca2 Cu3 O8+x. few months later, another team measured superconductivity above 150K in the same compound under applied pressure (153 K at 150 k bar)

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