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arXiv · 0806.3925

Energy minimization and AC demagnetization in a nanomagnet array

X. Ke·J. Li·C. Nisoli·Paul E. Lammert·W. McConville·R. F. Wang·V. H. Crespi·P. Schiffer
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Abstract

We study AC demagnetization in frustrated arrays of single-domain ferromagnetic islands, exhaustively resolving every (Ising-like) magnetic degree of freedom in the systems. Although the net moment of the arrays is brought near zero by a protocol with sufficiently small step size, the final magnetostatic energy of the demagnetized array continues to decrease for finer-stepped protocols and does not extrapolate to the ground state energy. The resulting complex disordered magnetic state can be described by a maximum-entropy ensemble constrained to satisfy just nearest-neighbor correlations.

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X. Ke, J. Li, C. Nisoli, Paul E. Lammert, W. McConville, R. F. Wang, V. H. Crespi, P. Schiffer. 2008-08-06. Energy minimization and AC demagnetization in a nanomagnet array. https://doi.org/10.1103/physrevlett.101.037205

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