Abstract Scope |
Eutectoid decomposition of bulk Co-Pt alloys in the A1 phase, with composition near 60% Pt, can result in formation of the unique nanochessboard structure. The nanochessboard is a self-assembled, 2+1D-periodic stacking of magnetically hard L10 nanorods embedded in a soft L12 matrix, all separated by coherent interfaces. Lateral lengthscales of the chessboard range from 20-40 nm. As such, the chessboard is a fascinating structure in which to examine exchange coupling, since it exhibits intermediate complexity between epitaxial bilayers and nanocrystalline aggregates. This talk will show how ferromagnetic exchange-coupling depends on lengthscale, quantify the role of hierarchical structure on the coercivity, and discuss insights into the exchange coupling and magnetization reversal mechanisms obtained from micromagnetics simulations. Recent attempts to synthesize nanochessboards in the advantageous Fe-Pt system will also be discussed. Support of the National Science Foundation through grants DMR-1105336 and DMR-1709914 is gratefully acknowledged. |