In modern physics of the past century, understanding the electronic properties and interactions between electrons inside matter has been a major challenge. Electrons are responsible for the chemical link between atoms and almost all factors that characterise a piece of matter, such as colour, heat transport, conductivity and magnetism. An elementary property of electrons is the spin, and the combination of electronic spins on the atomic level can induce a magnetic moment on certain atoms, which constitute the material. These moments can add up to macroscopic magnetic forces.