Magnetic nanoparticles through sonochemistry

Synthesis of nanomaterials using ultrasound induced cavitation is a relatively new technique which is becoming prominent. Cavitation induced by acoustic waves results in the creation and collapse of microbubbles which provide extreme synthesis conditions such as: temperatures of ∼5000 K, pressures of ∼1 GPa and cooling rates of ∼1010 K s–1. Synthesis of materials under these non-equilibrium conditions is termed as 'sonochemistry'. Various types of materials have been synthesised using this technique and the present review discusses only magnetic materials. Metals, alloys and oxides both in isolated and composite form have been synthesised using sonochemistry. Since the process duration is extremely short the resulting particles will be of nanosize. The magnetic behaviour of these nanosize particles differs from the bulk equivalents and these properties of different materials synthesised are also discussed.