Nanocrystalline YCrO_3 with onion-like structure and unusual magnetic behaviour

摘要

Nanocrystalline YCrO_3 powder was synthesized by a combustion technique using glycine as the fuel and the corresponding metal nitrates as oxidants. Three different oxidant-to-fuel ratios namely fuel-deficient, stoichiometric and fuel-excess ratios were chosen to explore the possibility to prepare single-phasic YCrO_3. The crystallite size for the phase pure product after calcination at 600 deg C was found to be 36 nm by x-ray line broadening. The agglomerate behaviour was investigated by light scattering studies. The TEM observations clearly highlight the pronounced crystallinity for YCrO_3. A striking observation was the presence of onion-like layers in HR-TEM micrographs. Magnetic measurements reveal the weak ferromagnetic nature of YCrO_3 nanoparticles, although the bulk YCrO_3 is reported to be an antiferromagnetic material.