Fundamental material issues in magneto-optical recording

Abstract

The magnetic properties of thin films and multilayered structures for magneto-optical (MO) recording applications strongly depend on the local atomic environment and microstructure. To arrive at an atomistic description of the origins of the large perpendicular magnetic anisotropy in these materials, we have utilized a variety of structural probes such as EXAFS, Synchrotron X-ray Diffraction, High Resolution TEM, X-ray Photoelectron Diffraction and STM. These techniques allow us to probe both the local environment and long range order. We have established that in amorphous alloys of the rare earth - transition metal groups, structural anisotropy is present in the form of Bond Order Anisotropy (BOA) which we attribute is the origin of the magnetic anisotropy. Similarly, the structural origins of the out-of-plane magnetic anisotropy in Co/Pt multilayers and superlattices is currently under investigation by a variety of growth techniques including MBE, sputtering and UIIV evaporation. The structural order is again investigated utilizing structural probes that provide details on atomic stacking and local order. This approach allow us to establish correlations between growth orientation, microstructure and magnetic properties as well as to obtain an atomic description of the interface structure which plays a pivotal role in the collective behavior of these materials.