Low-temperature combustion synthesis of nanocrystalline HoFeO₃ powders via a sol–gel method using glycin

Abstract

Single phase nanocrystalline HoFeO₃ powders were successfully synthesized by the sol–gel self-propagation combustion method using glycin (C₂H₅NO₂) as the chelating reagent at a low combustion temperature. Four different mole ratios of glycin to metal nitrate (G/M) were used to prepare HoFeO₃ powders in the experiment. The XRD patterns indicate monophasic HoFeO₃ powders can be formed by further calcination, the SEM micrographs show that the nano-sized grains with distinguishable boundaries had been obtained. The M–H curves show HoFeO₃ powders had the characteristic of antiferromagnetism at 50 K, while the powders had the characteristic of paramagnetism as the ambient temperature reached 100 K or 300 K. The FC/ZFC magnetic measurement results demonstrate that there was a transition from antiferromagnetism to paramagnetism in HoFeO₃ nanopowders as the temperature was increased.