Surface and shape anisotropy effects in LaFeO3 nanoparticles

The magnetic properties of the LaFeO3 nanospheres and nanotubes prepared by using the molten salt method have been investigated by magnetization measurements. The zero-field-cooled (ZFC) curve for the LaFeO3 nanospheres exhibits a maximum at 44 K while the ZFC curve for the LaFeO3 nanotubes exhibits two maxima: one, at 48 K, and the other, at 5 K. The maximums at 44 K and 48 K are ascribed to the average blocking temperature of the core moment. The maximum at 5 K in the ZFC curves for the LaFeO3 nanotubes and the rapid increase of magnetization below 10 K in the field-cooled (FC) curves for the LaFeO3 nanotubes are attributed to the surface spin freezing and the tube morphology. Hysteresis loops for the LaFeO3 nanospheres and nanotubes are measured. Loop shift for the LaFeO3 nanospheres is observed and discussed. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3590389]