Regensburg 2019 – scientific programme
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MA: Fachverband Magnetismus
MA 51: Magnetism Poster B
MA 51.65: Poster
Thursday, April 4, 2019, 15:00–18:00, Poster C
Atom-by-atom engineering of associative memories in finite size spin systems — Alex Kolmus1, Mikhail Katsnelson2, •Alexander Khajetoorians2, and Hilbert Kappen1 — 1Donders Institute for Neuroscience, Nijmegen, The Netherlands — 2Institute for Molecules and Materials, Nijmegen, The Netherlands
We demonstrate that a two-dimensional finite and periodic array of spins coupled via RKKY-like exchange can exhibit tunable magnetic phases ranging from robust double well potentials, multi-well attractor potentials, towards spin glass-like landscapes. These magnetic phases can be tuned by one gate-like parameter, namely the ratio between the lattice constant and the long-range interaction wavelength. We characterize theoretically the various magnetic phases, quantifying the distribution of low energy states, aging relaxation dynamics, and scaling behavior. The glassy and multi-well behaviors result from the competing character of RKKY interactions at different distances, no disorder is assumed. The multi-well structure features multiple attractors, each with a sizable basin of attraction, which are the requirement for associative memory. We show that by embedding the atom array in a bi-associative memory, we obtain a learnable associative memory system.