Size-dependent magnetic properties of high oxygen content YMn₂ O_5±δ multiferroic nanoparticles

The effect of particle size on magnetic properties in single-crystalline multiferroic YMn₂ O_5.07 nanoparticles was investigated. A modified Pechini's method was employed to synthesize YMn₂ O _5.07 powders with different particle sizes under an atmosphere of 10 bar O₂. It was found that the multiferroic YMn₂ O _5.07 compound displays a profound size dependence in its magnetic properties when the particles were smaller than 160 nm. With a decrease in particle size, a ferromagnetic-like phase with a broad transition emerges and the transition temperature increases. This ferromagnetic-like phase might be attributed to the surface layer of the nanoparticles and the broad magnetic transition could be caused by the dispersion of particle size and the size dependence of the transition temperature.