We have studied the moment correlations within triangular lattice arrays of single-domain co-aligned nanoscale ferromagnetic islands. Independent variation of lattice spacing along and perpendicular to the island axis tunes the magnetostatic interactions between islands through a broad range of relative strengths. For certain lattice parameters, the sign of the correlations between near-neighbor island moments is opposite to that favored by the pair-wise interaction. This finding, supported by analysis of the total correlation in terms of direct and convoluted indirect contributions across multiple pairwise interactions, indicates that indirect interactions and/or those mediated by further neighbors can be tuned to be dominant, with implications for the wide range of systems composed of interacting nanomagnets.
Cite
@article{arxiv.1108.1506,
title = {Ignoring your neighbors: Moment correlations dominated by indirect or distant interactions in an ordered nanomagnet array},
author = {Sheng Zhang and Jie Li and Jason Bartell and Xianglin Ke and Cristiano Nisoli and Paul E. Lammert and Vincent H. Crespi and Peter Schiffer},
journal= {arXiv preprint arXiv:1108.1506},
year = {2012}
}