Magnetism on a Microscopic Scale

Abstract

Tremendous progress has been made in the field of magnetic-materials research and technology over the past few years. Superior properties and novel scientific questions arise from our ability to either synthesize artificial structures or tailor microstructures at the appropriate length scale. The development of enhanced macroscopic properties in such materials requires, in addition to synthesis, that the magnetic microstructure be quantitatively determined and its dependence on the physical/chemical microstructure at the appropriate length scale be understood. Such studies are also motivated by the technologies of information storage, magnetic and magnetooptic recording, sensors, and magnetic devices. While these applications have been the focus of earlier issues of the MRS Bulletin, here we emphasize the physics, materials science, novel magnetic measurements, and micromagnetics, as well as the implications of this work on emerging technologies.Magnetism, subtle in its manifestations, is electronically driven but weak compared to electrostatic interactions. It is quantum-mechanical in nature with its origins in the Pauli exclusion principle and the existence of electron spin. However, it is known for a variety of both classical and quantum-mechanical effects stemming from both short- and long-range forces. It has a wide association with what is traditionally known as “microstructure” or the morphological arrangement of phases, grains, or individual atoms themselves. These factors are in part the reason for the richness of structures and properties encountered in magnetic systems from which many useful engineering and technical applications arise. They are also in part the reason why magnetism remains poorly understood and why many fundamental questions remain unanswered.