Figure 4.

SEM micrographs of the MgFe2O4/PVP composite samples calcined in air at different temperatures for 2 h.a500 °C,b600 °C,c700 °C, andd800 °C

Maensiri et al. Nanoscale Research Letters 2008 4:221   doi:10.1007/s11671-008-9229-y