Spinel type copper sulfides, Cu1+x
Rh2-x
S4(x=0–1) and Cu1-x
Co2-x
S4(x=0–0.75), were synthesized, and the crystallographic properties, ac and dc susceptibilities and electrical resistivity were experimentally studied in relation with their magnetic and superconductive properties.
Cu1+x
Rh2-x
S4 showed Pauli paramagnetism, metallic conductivity and a superconducting transition at 4.75 K with a ∼100% Meissner fraction. The copper doping in the B site did not cause any prominent effect on these properties. In contrast to this, Cu1+x
Co2-x
S4 showed a Curie-Weiss type antiferromagnetic susceptibility with a constant term χ0=2.35×10-6 emu/Oe·g, Néel temperature T
n=18.0 K, effective Bohr magneton µeff=0.89µB/f.u. and paramagnetic Curie temperature θP=-52 K. AC susceptibility showed diamagnetism due to superconductivity as x increases and reached ∼100% Meissner fraction at x=0.5. Metallic type resistivity was observed for the whole range of x. The zero resistivity temperature depends on x and is 2.3 K for x=0.5. It was concluded that the magnetic moment of the itinerant 3d hole of Cu2+(3d9) in the system Cu1+x
Co2-x
S4 orders antiferomagnetic way below the Néel temperature and transfers to or coexists with a superconductive state below the critical temperature. The copper doping in the B site thus caused a prominent effect on the superconductivity, on which collaborative effect of the coexisting second phases of Cu7S4 and Cu9S4 with the XRD intensity of 0.5–5% still remains to be clarified.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.