X-ray Diffraction and ⁵⁷Fe Mössbauer Spectroscopy Studies of Co-Doped AgFeO₂

Abstract

Delafossite AgFe1−xCoxO2 (x = 0, 0.05, 0.1, 0.2) powders were synthesized by co-precipitation method. The structural analysis and hyperfine interactions investigations were performed by X-ray diffraction and the Mössbauer spectroscopy. It was found that the Co-doped delafossite phase with traces of metallic silver was obtained. The investigated samples were fine powders which are typical of the materials synthesized by co-precipitation. The Mössbauer spectroscopy studies revealed random incorporation of cobalt ions into the crystalline lattice of delafossite. Doping of cobalt ions caused the distortion of the oxygen octahedra in AgFeO2 which was observed in the increase of the quadrupole splitting value.

X-RAY DIFFRACTION AND MÖSSBAUER SPECTROSCOPY INVESTIGATIONS OF THE (Al, Ni, Co)-DOPED AgFeO2 SYNTHESIZED BY HYDROTHERMAL METHOD

“…1). Similarly, as it was reported in [17] for the AgFe 1-x Co x O 2 (x = 0-0.2) series of samples synthesized by the co-precipitation method there were no peaks indicated another impurity phase. The absence of the CoO, NiO, and Al 2 O 3 oxides can prove that our attempt the replacing the Fe ions with Al, Ni, and Co ions in the delafossite structure was realized successfully.…”

“…It can mean a better level of crystallinity of the hydrothermally synthesized materials and a lower amount of defects in the crystalline structure in comparison to co-precipitated powder samples of AgFeO 2 .In the case of AgFe 0.9 Al 0.1 O 2 , AgFe 0.9 Ni 0.1 O 2 , and AgFe 0.9 Co 0.1 O 2 samples additional peaks, marked as metallic silver, are visible in the diffractograms (Fig.1). Similarly, as it was reported in[17] for the AgFe 1-x Co x O 2 (x = 0-0.2) series of samples synthesized by the co-precipitation method there were no peaks indicated another impurity phase. The absence of the CoO, NiO, and Al 2 O 3 oxides can prove that our attempt the replacing the Fe ions with Al, Ni, and Co ions in the delafossite structure was realized successfully.Bringing the assumption that B 3+ should replace Fe 3+ ions during substitution, the appearance of metallic silver is quite unexpected.…”

“…Parameters are comparable for all studied Al, Ni, and Co-doped silver ferrites. Their values are slightly higher in comparison to the results obtained in our work for AgFeO 2 synthesized by the co-precipitation method [17]. Moreover, the significant anisotropic broadening of diffraction lines observed in the case of co-precipitated materials is not seen now in XRD patterns registered for AgFe 0.9 Al 0.1 O 2 and AgFe 0.9 Co 0.1 O 2 (Fig.…”