Abstract

Starch from the stem of sago palm (Metroxylon sagu) was demonstrated as a chelating agent in the sol-gel synthesis of cobalt ferrite (CoFe<inf>2</inf>O<inf>4</inf>) nanoparticles. Variations in the weight ratio of metal nitrates to sago starch from 1:8 to 1:12 led to the particle size of 30-500 nm. However, further increase in sago starch to 1:16 resulted in ferrimagnetic hysteresis loops with a reduced coercive field and magnetization due to the second phase of hematite (α-Fe<inf>2</inf>O<inf>3</inf>). The synthesis conditions and products were comparable to those of the polyvinyl alcohol (PVA) sol-gel synthesis. Thus, sago starch can be implemented in the green synthesis of nanosized ferrites whose magnetic properties are tuned by varying of sol-gel compositions for each application.