Mg substitution in CuCrO2 delafossite compounds

Abstract

A detailed investigation of the series CuCr(1-x)MgxO2 (x = 0.0 - 0.05) has been performed by making high-temperature resistivity and thermopower measurements, and by performing a theoretical analysis of the latter. Microstructure characterization has been carried out as well. Upon Mg2+ for Cr3+ substitution, a concomitant decrease in the electrical resistivity and thermopower values is found, up to x ~ 0.02 - 0.03, indicating a low solubility limit of Mg in the structure. This result is corroborated by scanning electron microscopy observations, showing the presence of MgCr2O4 spinels as soon as x = 0.005. The thermopower is discussed in the temperature-independent correlation functions ratio approximation as based on the Kubo formalism, and the dependence of the effective charge carrier density on the nominal Mg substitution rate is addressed. This leads to a solubility limit of 1.1% Mg in the delafossite, confirmed by energy dispersive X-ray spectroscopy analysis.

6 pages, 5 figures

References in corpus (6)

• Unconventional Dynamics in Triangular Heisenberg Antiferromagnet NaCrO2
• On the metallic conductivity of the delafossites PdCoO2 and PtCoO2
• On the strong impact of doping in the triangular antiferromagnet CuCrO2
• Electronic structure and thermoelectric properties of CuRh(1-x)MgxO2
• Long-range magnetic order and spin-lattice coupling in the delafossite CuFeO2
• Spin dynamics in triangular lattice antiferromagnets CuCr${}_{1-x}$Mg${}_x$O${}_2$

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