New family of high <i>Tc</i> superconductors in the (Tl1−<i>x</i> <i>M</i> <i>x</i>)Sr2(Ca1−<i>y</i>Y<i>y</i>)Cu2O7−δ system (<i>M</i>=IVA and VA elements)

Abstract

A new family of high Tc superconductors with superconducting transition temperatures ranging from 40 to 100 K have been synthesized in the (Tl1−xMx)Sr2 (Ca1−yYy)Cu2O7−δ (M=Ti, Zr, Hf, V, Nb, and Ta) system. Here, we use as an example, vanadium and yttrium substitution into the thallium and calcium sites, respectively, in the parent compound TlSr2CaCu2O7 to demonstrate the substitutional chemistry, crystal structure, and superconductivity for these new superconductors.