We report an experimental and theoretical study of magnetic properties of synthetic
eumelanin. The magnetization curves are determined by using both a vibrating sample
magnetometer and a superconducting quantum interferometer device in an extended range
of magnetic fields ranging from− 10 kOe to 10 kOe at different temperatures. We find that the
eumelanin magnetization can be qualitatively explained in terms of a simple model of
dipolar spheres with an intrinsic magnetic moment. The latter one is experimentally …