Superconductivity and magnetic order in thallium-based cuprates

A series of polycrystalline samples of system TlA(2)RCu(2)O(7-x) (A = Sr, B e; R = RE, Y and Ca) with perovskite-like 1212-structure has been synthesiz ed and investigated by magnetic and transport measurements in the temperatu re range of 4.2-300 K. The measurements revealed that along with high-tempe rature superconductivity, some of these compounds exhibit spontaneous antif erromagnetism, held-induced antiferromagnetism or ferromagnetism, Different types of magnetic ordering have been found depending on rare-earth ions lo cated in R position. The phenomenon of phase separation to magnetic and sup erconducting phases has probably been observed in a number of compounds. (C ) 2001 Elsevier Science B.V. All rights reserved.