Characterization of the Y–Fe–O ultrafine particles containing a new compound YFe(3+x)O1.5(4+x) synthesized by rf thermal plasmas

We synthesized Y–Fe–O ultrafine particles that contained YFe(3+x)O1.5(4+x), h-YFeO3, ε-Fe2O3, and γ-Fe2O3, by using an rf Ar–O2 thermal plasma evaporation method. The particles were characterized by using X-ray diffraction (XRD), transmission electron microscopy (TEM)/selected-area diffraction (SAD), inductively coupled plasma emission spectroscopy (ICP-ES), vibrating sample magnetometer (VSM) and Mössbauer spectrometry. YFe(3+x)O1.5(4+x) is a new compound that has not yet been registered in the Powder Diffraction File (PDF) database. Because YFe(3+x)O1.5(4+x) has a long-period, face-centered cubic structure, the maximum XRD peak was indexed by (444). The magnetic hysteresis loop measurements done by VSM showed that the particles contained either ferri- or ferromagnetic compounds. γ-Fe2O3 affected the saturation magnetization of the particles. However, we could not determine whether YFe(3+x)O1.5(4+x) is a ferri- or ferromagnetic compound, by using XRD, VSM, or Mössbauer spectrometry. Therefore, the magnetic properties of YFe(3+x)O1.5(4+x) should be further investigated.