GROWTH AND CHARACTERIZATION OF CUFEO2 SINGLE-CRYSTALS

In this paper, the first successful growth of CuFeO2 single crystals by applying the traveling solvent floating-zone technique is reported. Typical crystals of 5-8 mm in diameter and 10-30 mm in length have been obtained from the starting materials Cu2O and Fe2O3 with the molar ratio 1:1. The as-grown crystal is homogeneous and of the trigonal system with cell parameters a(h) = 3.04 Angstrom and c(h) = 17.17 Angstrom in the hexagonal description. In Mossbauer effect (ME) measurements, the isomer shift for (57) Fe in CuFeO2 at room temperature is 0.40 mm/s with respect to metallic iron, which offers experimental confirmation that the iron is present in the trivalent state. Magnetic susceptibility measurements indicate that CuFeO2 has two successive magnetic transition temperatures at T-N = 13.5 K and T-N = 9.5 K, respectively. Thermal analysis reveals that CuFeO2 partially decomposes into Fe2O3 and Cu2O at about 1180 degrees C.