Morphology control of YMn2O5 nanocrystals by hydrothermal synthesis and their magnetic properties

Abstract

Single-crystalline YMn2O5 was successfully synthesized through a tunable hydrothermal route. The pH value of the growth solution was a crucial factor for the control of the size and morphology of YMn2O5. A low pH value led to the formation of nanorods. Both the final size of the nanocrystals and their aspect ratio increased drastically with decreasing pH value. A relatively high temperature and low metallic salt concentrations favored the formation of one-dimensional nano-crystalline YMn2O5. Magnetic measurement indicated the crystalline YMn2O5 showed a weak ferromagnetic ordering, which was explained by uncompensated spins at the surface. The magnetic susceptibility indicates that the ferromagnetic transition temperature increases from 39 to 42 K with increasing grain size from 80 to 600 nm. With the decrease in the particle size, the coercivity increases while the exchange bias decreases.