Atomically Layered Structures for Perpendicular Magnetic Information Storage

Abstract

ABSTRACTLayered structures can possess a high volumetric density of interfaces, which can result in novel magnetic properties. We report magnetic characteristics of two types of atomically layered structures, (001) oriented intermetallics with the CuAu(I) crystal structure and (111) oriented artificial multilayers. C-axis oriented superlattices of PtFe, PtCo, PdFe and PdCo with the layered CuAu(I) structure, possess large magnetic anisotropies and novel magneto-optic properties relative to the corresponding random alloys. These films are produced by annealing, with tetragonality and magnetic anisotropy developing in a fashion which depends on the initial bilayer period and annealing parameters. (111) oriented artificially grown Pd/CoCr multilayers are reported for perpendicular magnetic recording applications. Using a perpendicular contact probe transducer, the multilayers exhibit two times the readback signal of CoCr media. The multilayers can be made with low roughness suitable for contact recording, and can generate narrow readback pulses with large amplitude. Many aspects of Pd/Co performance, such as overwrite, can be predictably optimized for a given set of transducer properties. The reported results show that compositionally modulated structures can be made which have a wide variety of useful properties for perpendicular hard disk and magneto-optic recording.