Pressure Effect on the Transport and Magnetic Properties for the Hole-Doped Delafossite Oxide CuCr0.97Mg0.03O2 Having an S = 3/2 Antiferromagnetic Triangular Sublattice

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We investigated an effect of hydrostatic pressure (P) up to 14 GPa on a resistivity (\rho) of a hole-doped delafossite oxide CuCr0.97Mg0.03O2 having an S = 3/2 antiferromagnetic (AF) triangular sublattice. In contrast to a non-monotonic P-dependence of \rho, an AF transition temperature (T_{\text{N}}\approx T_{\text{peak}}) deduced from a peak temperature (T_{\text{peak}}) of a temperature dependence of local activation energy monotonically increases with the increase of P. The monotonic increase of T_{\text{peak}} without a large change of \rho mainly comes from an enhancement of an overlap between neighboring 3d orbitals of Cr ions, which suggests that the intrinsic effect of itinerant hole on T_{\text{N}} in CuCrO2 must be more dramatic than the observed one of the Mg substitution accompanying negative chemical pressure.
2011-07-15