Write, store and read are the three basic operations of information storage.  The knowledge of the basic physics of magnetism coupled with a rapid transfer of this knowledge to
industry has allowed us to perform these basic operations faster and in a smaller area with each succeeding generation of storage devices.  Currently the areal density of information has been increasing at the rate of 60% per year and the price per megabyte of storage capacity has been concurrently decreasing at the rate of 30% per year.  Sustaining these improvements is possible through rapid advances in physics and technology. 

Understanding magnetism on the fundamental level is one of the most challenging problems in condensed matter physics.  Since magnetism involves spin, it is an inherently quantum mechanical phenomenon.  The application of new probes that reveal the relationship between crystal structure, electronic structure, and magnetic properties, coupled with a theoretical advancements, has resulted in a more complete description of magnetism. 

The probes we use to study magnetism are sources of radiation.  In the laboratory at UA we use polarized laser light (electromagnetic radiation) which changes its polarization state when it interacts with a magnetic surface.  Higher energy electromagnetic radiation in the ultraviolet and x-ray regions of the electromagnetic spectrum is used to probe the electronic and crystal structure of surfaces and interfaces.  In addition, nuclear radiation in the form of low-energy neutrons is used to probe the magnetic and crystal structure.