Abstract
Weak ferromagnetic order with ordering temperature Tm ~47 K and possible superconducting transition with Tc ~37 K are observed for the ruthenium-cuprate RuCa2 PrCu2 O8+δ with the orthorhombic distortion of the tetragonal RuSr2 GdCu2 O8+δ -type [with Tm ~136 K and Tc (max) ~65 K] phase. Anomalous temperature dependent magnetization Mm (T) in both field-cooled and zero-field-cooled modes and isothermal magnetic hysteresis Mm (Ba) below and above Tm and Tc indicates a very complicated coexistence and interplay between weak-ferromagnetic order and possible superconductivity. © 2005 American Institute of Physics.