Nanoparticles of magnesium cobalt ferrites

Take Manganese nitrate, cobalt nitrate and ferric nitrate in the weight ratio 1:1:1. Dissolve in distilled water and make it a rich paste. Keep this paste in a oven and heat it to 400 Kelvin temperature. Dried sample crush using agate mortar till it becomes fine powder. Keep this powder in a bowl of high energy ball milling unit. Mill it for more than 5 hours with a minimum of 500 rotations per minute speed. Resulting powder is the fine form of nanoparticles of magnesium cobalt ferrites.