Magnetization dynamics in artificial spin ice made from magnetic tunnel junctions
Phys. Rev. Applied 25, 044044 – Published 16 April, 2026
DOI: https://doi.org/10.1103/yh6q-mcnb
Abstract
The fast dynamics of square lattice artificial spin ice made of circular magnetic tunnel junctions are investigated through magnetoresistance measurements on individual 60-nm devices. The common fixed layer leads to easy- and hard-axis behavior: devices that telegraph between parallel and antiparallel states, alternating with devices where the free-layer moment rotates. Preferred canting angles are observed and can be related to predictions based on the magnetostatic fields from near neighbors. Two timescales are observed, one corresponding to single nanomagnet fluctuations and the other to mesoscale rearrangements. Devices in canted states are part of nodes with nonzero net magnetic charge, known as emergent magnetic monopoles. While monopole-containing states are abundant, these excitations are often long-lived and their lifetime depends on the stability of the mesoscale flux closure patterns.
