Cationic doping effect on the structural, magnetic and spectroscopic properties of delafossite oxides CuCr1−x(Sc,Mg)xO2

This article reports the effect of Sc and (Sc + Mg) substitution on the structural and physical properties of delafossite-type CuCrO2 oxide. X-ray diffraction and Raman spectroscopy show that the structure is maintained for 10% Sc and (10% Sc + 4% Mg) substitutions for chromium. The incorporation of these elements generates very anisotropic microstrains in the structure. Strain also increases with oxygen intercalation, probably because a non-uniform distribution of intercaled oxygen. Thermal stability in oxygen was found to decrease with increasing the M3+ cation size. The evolution of relative intensities of Raman bands points towards an increase in lattice distortion with substitution, in agreement with ionic radii considerations. Comparing the substitution effect of Mg2+ to those of the nonmagnetic Sc3+, magnetization around the AF transition does not seem to correlate with randomness and lattice parameter but with itinerancy of the doped hole.