Magnetization dynamics using time-resolved magneto-optic microscopy

Abstract

The physics of magnetism in small magnetic elements, where the thickness and lateral dimensions are on the nanometer scale, has become one of the most vigorous research areas in condensed matter physics [l-31. The subject of nanomagnetism is stimulated both by discoveries of a steadily increasing range of magnetic phenomena and by the increasing interest in advanced magnetic information storage and data process technology. Over the last decades, novel physics has been found in ultrathin magnetic materials. These include the two-dimensional (2D) magnetic phase transition, magnetic interactions, surface magnetic anisotropies and 2D magnetic ordering phenomena, which have all yielded important new fundamental insights. Particularly important findings from the application point of view include the discovery of the giant magnetoresistance (GMR) effect [4], interlayer exchange coupling, and spin-dependent tunneling. Tremendous possibilities of novel magnetic phenomena for technological applications become immediately apparent by considering that most of the information we deal with is processed and stored magnetically, from audio and video products to information storage on computer hard disks. GMR gives one example of such practical applications, where its extreme sensitivity to the magnetic field is used in computer hard disks to enhance information storage density.