The influence of Cu substitution for Ru on the magnetic behaviour of a weak ferromagnet, Ca₃LiRuO₆

The influences of gradual Cu substitution for Ru on the magnetic characteristics of a weak ferromagnet, Ca₃LiRuO₆ (with a magnetic ordering temperature of 113 K), are reported as obtained by magnetization studies. We find that single-phase compounds could be formed only until x = 0.3 in Ca₃LiRu_1-xCu_xO₆. We do not find evidence for superconductivity in the temperature range of the investigation (2-300 K). The onset of magnetic ordering is depressed only marginally with Cu substitution (to about 90 K for x = 0.3), which indicates that the magnetic interaction along the chain is not predominantly of a long-range type, but rather of a short-range (superexchange?) type. There are notable changes in the magnetic field/temperature dependence of the magnetization, as if there are dramatic changes in the magnetic structure.