Time: Friday, October 12th, 11:00
Speaker: Alexander Ako KHAJETOORIANS, Radboud University
We demonstrate that a two-dimensional periodic array of spins coupled via RKKY-like exchange can exhibit tunable energy landscapes ranging from robust double-well toward spin glasses. We characterize the magnetic ground states and energy landscapes of such arrays, by the distribution of low energy states, energy barriers, aging relaxation dynamics and the size of the basins of attraction. We identify three phases resulting from singularly varying the RKKY period: a double well phase, a spin glass phase and a multi-well phase. The spin glass behavior results from self-induced glassiness, which is driven by the incommensurability of the RKKY period and the periodic array. We address these different phases considering scaling and aging arguments. Finally, we argue that the tunable complexity of these spin arrays can function as an associative memory (Hopfield network) at the atomic scale, and illustrate these memories for a given lattice and a scheme for pattern recognition.