Magnetism comes to light

With the ever-increasing demand for high-density data storage comes the necessity for a thorough understanding of magnetic materials, Here, we highlight two of the most important new effects in magnetic thin film technology - perpendicular magnetic anisotropy and giant magnetoresistance - and briefly discuss the origin of magnetism, specifically magnetocrystalline anisotropy. Techniques used in the study of these materials are many and varied, but one has proved particularly successful - we show how circularly polarized X-rays from the Synchrotron Radiation Source (SRS) at Daresbury Laboratory can be used to retrieve information about the spin and orbital components of the magnetic moment from films of less than one atomic monolayer.