Superparamagnetism

Superparamagnetism is a phenomenon observed in small magnetic particles, typically less than 10 nanometers in size. In these particles, thermal energy can overcome the magnetic interactions that keep them aligned, allowing their magnetic moments to flip randomly. As a result, they do not retain magnetization when the external magnetic field is removed, unlike larger magnets. This behavior leads to high magnetic susceptibility, meaning they can become magnetized very easily but lose this magnetism quickly when the field is removed. Superparamagnetic materials are used in applications like magnetic nanoparticles in medicine and data storage technologies.