MOSSBAUER-SPECTRA AND MAGNETIC-SUSCEPTIBILITIES OF ULTRAFINE HEXAGONAL RFEO(3) (R-EU,YB) PARTICLES FORMED BY THE SPRAY INDUCTIVELY-COUPLED PLASMA TECHNIQUE

Ultrafine RFeO(3)(R=Eu, Yb) particles were synthesized by introducing atomized solutions containing metal salts into a high temperature indu ctively coupled plasma (the spray-ICP technique). The particles exhibi ted an X-ray diffraction pattern that can be interpreted as an analogu e of hexagonal (h) YAlO3. They were converted to orthorhombic RFeO(3) at high temperatures above 800 degrees C, and hence can be regarded as metastable compounds. Transmission electron microscopy revealed that the particles are hexagonal platelets 10-50 nm in width. Mossbauer spe ctroscopy indicated that the iron is trivalent with two different site s, 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 paramagne tic moments of the Curie-Weiss law with the trivalent iron and rare ea rth ions.