Title :
Spring magnet films
Author :
Jiang, I.S. ; Fullerton, E.E. ; Sowers, C.H. ; Inomata, A. ; Bader, S.D. ; Shapiro, A.J. ; Shull, R.D. ; Gornakov, V.S. ; Nikitenko, V.I.
Author_Institution :
Div. of Mater. Sci., Argonne Nat. Lab., IL, USA
fDate :
9/1/1999 12:00:00 AM
Abstract :
The properties of exchange-spring-coupled bilayer and superlattice films are highlighted for Sm-Co hard magnet (nominally Sm2Co 7) and Fe or Co soft magnet layers. The hexagonal Sm-Co is grown via magnetron sputtering in a- and b-axis epitaxial orientations. In both cases the c-axis, in the film plane, is the easy axis of magnetization. Trends in coercivity with film thickness are established and related to the respective microstructures of the two orientations. The magnetization reversal process for the bilayers is examined by magnetometry and magneto-optical imaging, as well as by simulations that utilize a one-dimensional model to provide the spin configuration for each atomic layer. The Fe magnetization is pinned to that of the Sm-Co at the interface, and reversal proceeds via a progressive twisting of the Fe magnetization. The Fe demagnetization curves are reversible as expected for a spring magnet. Comparison of experiment and simulations indicates that the spring magnet behavior can be understood from the intrinsic properties of the hard and soft layers. Estimates are made of the ultimate gain in performance that can potentially be realized in this system
Keywords :
cobalt; cobalt alloys; coercive force; crystal microstructure; demagnetisation; exchange interactions (electron); iron; magnetic epitaxial layers; magnetic multilayers; magnetisation reversal; magneto-optical effects; metallic superlattices; permanent magnets; samarium alloys; soft magnetic materials; sputtered coatings; C; Fe; Fe demagnetization; Fe magnetization; Sm-Co hard magnet; Sm2Co7; coercivity; easy axis of magnetization; epitaxial orientations; exchange-spring-coupled bilayer; film thickness; hexagonal Sm-Co; intrinsic properties; magnetization reversal process; magneto-optical imaging; magnetometry; magnetron sputtering; microstructures; one-dimensional model; orientations; performance gain; simulations; soft magnet layers; spin configuration; spring magnet films; superlattice films; Atomic layer deposition; Coercive force; Iron; Magnetic properties; Magnetic superlattices; Magnetization reversal; Microstructure; Soft magnetic materials; Springs; Sputtering;
Journal_Title :
Magnetics, IEEE Transactions on
