  The samples of composition RuSr2(Ln3/4Ce1/4)2Cu2O10 with Ln = Ho, Y and Dy.
being synthesized by high pressure high temperature (6Gpa, 1200 0C) solid state
synthesis route do crystallize in space group I4/mmm. These samples exhibit
magnetic transitions at ~150 K with significant branching of zfc
(zero-field-cooled) and fc (field-cooled) magnetization and a sharp cusp in zfc
at ~ 100 K, followed by a superconducting transition at lower temperatures. All
the compounds show typical ferromagnetic hysteresis loops in magnetic moment
(M) versus 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 ~ 0.80 muB.
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.
