High Quality Content by WIKIPEDIA articles! In quantum physics, the spin–orbit interaction (also called spin–orbit effect or spin–orbit coupling) is any interaction of a particle`s spin with its motion. The first and best known example of this is that spin-orbit interaction causes shifts in an electron`s atomic energy levels due to electromagnetic interaction between the electron`s spin and the magnetic field generated by the electron`s orbit around the nucleus. This is detectable as a splitting of spectral lines. A similar effect, due to the relationship between angular momentum and the strong nuclear force, occurs for protons and neutrons moving inside the nucleus, leading to a shift in their energy levels in the nucleus shell model. In the field of spintronics, spin-orbit effects for electrons in semiconductors and other materials are explored for technological applications. The spin-orbit interaction is one cause of magnetocrystalline anisotropy.