Nanocrystallization Kinetics and Induced Anisotropy in Soft Magnetic Nanocomposites

Carnegie Mellon University, Pittsburgh PA

Investigators

Abstract

This award by the Division of Materials Research to Carnegie Mellon University is to study synthesis, structure and property relationships in soft magnetic nanocomposite materials that show promise for applications in energy conversion and data storage. With this award, Professors McHenry and Laughlin will study the following: (1) furthering present understanding of nanocrystallization kinetics as a tool for controlling magnetic microstructures; and (2) determining the relationship between microstructure (including magnetic field and domain structure induced microstructural changes) and soft magnetic properties of nanocomposite materials. Research studies will develop fundamental understanding of the synthesis, structure, and property relationships in nanocomposite soft magnetic materials in terms of: (a) refinement of models of the kinetics of nanocrystallization; (b) modeling chemical partitioning that occurs during nanocrystallization and its role in the temperature dependence of intergranular magnetic coupling; and (c) microstructural observations and magnetic property measurements aimed at elucidating the microscopic mechanisms for inducing magnetic anisotropy. These soft magnetic nanocomposites based on iron-cobalt-M-boron-copper (where the metal could be niobium, zirconium or hafnium) called HITPERM have promise for application in high temperature, high frequency inductive devices and inductive components in data storage. Miniaturization of power electronic components must consider inductive components and issues of frequency response (power density, losses) and thermal management. Thermally assisted writing on perpendicular recording media requires high temperature/high induction magnetic underlayers and write heads and low noise, soft magnetic layers in spin valve sensors. Magnetic nanocomposite materials development will benefit from a fundamental understanding of magnetic nanostructure/property relationships. Scientific interactions include activities at Georgia Institute of Technology and the National High Field Magnetic Laboratory on high field nanocrystallization experiments and National Institute for Materials Research (Tsukuba, Japan) for field ion microscopy. Research efforts will be coupled to educational initiatives aimed at teaching research methodology and communicating state of the art to undergraduates. The investigators at present teach a graduate course on Applied Magnetism and Magnetic Materials. This course syllabus will be revised so as to offer undergraduate course credit as an interface to the Magnetic Materials Track as part of the undergraduate curriculum. Two local industries, Seagate Corp. and Magnetics, Inc. will be consulted as to course content. This work couples with U. S. Air Force and NASA funded efforts to develop high frequency, high temperature inductive devices.