Synthesis of RuSr2(Ln3/4Ce1/4)2Cu2O10 magneto-superconducting compounds with Ln = Ho, Y and Dy by high-pressure high-temperature technique

The samples of composition RuSr2(Ln(3/4)Ce(1/4))(2)Cu2O10 with Ln = Ho, Y and Dy, being synthesized by high-pressure high-temperature (6 GPa, 1200 degreesC) solid-state synthesis route do crystallize in space group I4/mmm. These samples exhibit magnetic transitions at similar to150 K with significant branching of zero-field-cooled (zfc) and field-cooled (fc) magnetization and a sharp cusp in zfc at similar to100 K, followed by a possible superconducting transition at lower temperatures. All the compounds show typical ferromagnetic hysteresis loops in magnetic moment (M) vs. field (H) magnetization at 5 K. Near saturation of the moments at 5 K is achieved in above 5 T (Tesla) applied fields with a value of similar to0.80mu(B). At low temperatures (5 K) these compounds exhibit both superconductivity and ferromagnetism. To our knowledge these are first successfully synthesized Ru-1222 compounds with various lanthanides including Y, Dy, and Ho. The results are compared with widely reported Gd/Ru-1222 compound. (C) 2003 Elsevier Science B.V. All rights reserved.