Magnetic properties of RSr2RuCu2O8+delta (R = Eu and Gd)

The non superconducting RSr2RuCu2O8+delta (R = Eu and Gd) compounds are mag netically ordered below T-N = 168 and 185 K, respectively. Magnetic suscept ibility (ac and de) studies indicate that the magnetic ordering is due to t he Ru sublattice. The Gd sublattice in GdSr2RuCu2O8 is antiferromagneticall y ordered at 2.8 K. Irreversibility phenomena and magnetic anomalies, obser ved at low magnetic fields, originate from antisymmetric exchange coupling of the Dzyaloshinsky-Moria type, and from spin reorientation of the Ru mome nts. The magnetic behavior of this system and that of the well-known itiner ant ferromagnet SrRuO3 are compared. (C) 1999 Elsevier B.V.Science. All rig hts reserved.