The last 10 years have seen great interest in the magnetism of reduced dimensionality structures. Workers around the world have recently started to study 1-D and 0-D magnets by laterally structuring thin magnetic films into magnetic quantum wires and dots. As well as being an excellent experimental means of studying fundamental magnetic phenomena, these low dimensionality magnets may in the future form the basis of new data storage and computing technologies.

A new type of nanomagnetic probe uses the Magneto Optical Kerr Effect (MOKE), the phenomenon by which the polarisation of light is rotated when it is reflected from the surface of a magnetic material. The NanoMOKR probe can determine quantitative hysteresis loops from small arrays of nanomagnets or from individual nanomagnets.

The flexibility of nanoMOKE means that different types of measurement can be made with the same apparatus. Modulated Field Magneto-Optical Anisometry (MFMA) is a particularly useful measurement which allows the magnetic anisotropy surface of a nanomagnet to be mapped directly. This allows the magnitude, symmetry and orientation of any anisotropy present in the nanomagnet to be determined. The direction in the plot gives the direction in the nanomagnet, the radius in the plot gives the size of nanomagnet being considered and the color gives the anisotropy field. The square nanomagnet shows a 4-fold anisotropy. These anisotropies come from the shape of the nanomagnet and not from the basic material properties. This shows how fundmental magnetic properties such as anisotropy can be controlled and engineered in a precise fashion by nanometre scale structuring.