Antiferromagnet-Ferromagnet Transition in FeCuNbO.

Iron niobates, pure and substituted with copper (FeCuNbO with x = 0-0.15), were prepared by the solid-state method and characterized by X-ray diffraction, Raman spectroscopy, and magnetic measurements. The results of the structural characterizations revealed the high solubility of Cu ions in the structure and better structural stability compared to the pure sample.