This allows us to predict the magnetisation distribution inside any nanomagnet. We are then able to fabricate square and circular magnetic quantum dots of size 10-200nm and probe their magnetic properties in order to make a comparison with theory. Shown below is an example of a micromagnetic simulation of a magnetic vortex inside a square nanomagnet and an electron micrograph of experimentally made 100nm nanomagnets. We make our structures using a technique called electron beam lithography. This is a photographic process which uses a scanning electron microscope to project an image of the required structures onto a silicon substrate coated with a photosensitive resist layer.
Development removes only the resist which has been exposed to the electron beam.
A magnetic metal is then deposited, followed by lift-off of the unwanted metal. 3 Below are electron microscope pictures of some of the nanomagnets which we have studied. 4 Top of Page NanoMOKE probe Experimental techniques capable of measuring magnetic properties of magnetic structures on a nanometer scale form two classes. These probes can spatially resolve the magnetization distribution within a single magnetic element and so provide valuable information on the microscopic origin of magnetic behaviour. They are not, however, able to determine quantitative hysteresis loops.