Mössbauer spectra and magnetic susceptibilities of ultrafine hexagonal RFeO3 (R ≠ Eu, Yb) particles formed by the spray inductively coupled plasma technique

Ultrafine RFeO3(R ≠ Eu, Yb) particles were synthesized by introducing atomized solutions containing metal salts into a high temperature inductively coupled plasma (the spray-ICP technique). The particles exhibited an X-ray diffraction pattern that can be interpreted as an analogue of hexagonal (h) YA1O3, They were converted to orthorhombic RFeO3 at high temperatures above 800 °C, and hence can be regarded as metastable compounds. Transmission electron microscopy revealed that the particles are hexagonal platelets 10–50 nm in width. Mössbauer spectroscopy indicated that the iron is trivalent with two different sites, suggesting that the structure is slightly different from that of h-YAlO3 in the site number of iron. Magnetic susceptibility measurements in the temperature range 4.2–300 K showed that they satisfy paramagnetic moments of the Curie-Weiss law with the trivalent iron and rare earth ions.