Crystal structure and hyperfine interactions of delafossite (CuFeO2) synthesized hydrothermally

The powder specimen of CuFeO2 delafossite was synthesized by a hydrothermal method at 453 K. X-ray diffraction studies confirmed that the obtained pure delafossite phase was a mixture of the 3R and 2H polytypes, predominantly the former. Mössbauer spectral analysis revealed the paramagnetic state of the copper ferrite at room temperature. Below 12 K the spectra had complicated shapes of Zeeman sextets. Changes in the character of the hyperfine interactions did not correspond to the data reported for the single-crystal CuFeO2. Magnetization measurements revealed that magnetic transition occurred at Néel temperature (T N) = 12.5 K.