  We discuss the properties of new superconducting compositions of
Ru(1-x)Sr2RECu(2+x)O(8-d) (RE=Gd, Eu) ruthenocuprates that were synthesized at
600 atm. of oxygen at 1080 C. By changing ratio between the Ru and Cu, the
temperature of superconducting transition (Tc) raises up to Tc max=72 K for
x=0.3, 0.4. The hole doping achieved along the series increases with Cu->Ru
substitution. For x different than x=0, Tc can be subsequently tuned between Tc
max and 0 K by changing oxygen content in the compounds. The magnetic
characteristics of the RE=Gd and Eu based compounds are interpreted as
indicative of constrained dimensionality of the superconducting phase. Muon
spin rotation experiments reveal the presence of the magnetic transitions at
low temperatures (Tm=14-2 K for x=0.1-0.4) that can originate in the response
of Ru/Cu sublattices. RuSr2Gd(1-y)Ce(1-y)Cu2O8 (0<y<0.1) compounds show the
simultaneous increase of TN and decrease of Tc with y. The effect should be
explained by the electron doping that occurs with Ce->Gd substitution.
Properties of these two series allow us to propose phase diagram for 1212-type
ruthenocuprates that links their properties to the hole doping achieved in the
systems. Non-superconducting single-phase RuSr2GdCu2O8 and RuSr2EuCu2O8 are
reported and discussed in the context of the properties of substituted
compounds.
