**4.7 Magnetic properties**

There are two classes of NCs compounds exhibiting magnetic properties, one containing metal NPs and the other ferrite NPs. Basically, lack of hysteresis, shows 18 increased superparamagnetic activity in ferrite NPs. Nanocomposite containing 2.8% concentration of ferrites was found to have no hysteresis at room temperature and was clearly visible. They also found that nanocomposites containing γ-Fe2O3 NPs in the electromagnetic polymer matrix were also free of hysteresis. Nanoparticles from nickel oxide synthesis in Polyvinyl cinnamate also show magnetic properties. They found a ferromagnetic state in nickel nanocomposites. Additionally, weight gain, magnetic response, and hysteresis values are obtained with the incorporation of nickel oxide NPs on the nanocomposite material.
