Magnetic hysteresis of an artificial square ice studied by in-plane Bragg x-ray resonant magnetic scattering

• Published in: AIP advances Vol. 2; no. 2; pp. 022163 - 022163-10
• Main Authors: Morgan, J. P., Kinane, C. J., Charlton, T. R., Stein, A., Sánchez-Hanke, C., Arena, D. A., Langridge, S., Marrows, C. H.
• Format: Journal Article
• Language: English
• Published: United States AIP Publishing LLC 01.06.2012
• ISSN: 2158-3226; 2158-3226
• DOI: 10.1063/1.4732147

We report X-ray resonant magnetic scattering studies of a Permalloy artificial square ice nanomagnet array, focussing on the field-driven evolution of the sum Σ and difference Δ signals of left and right handed circularly polarized synchrotron X-rays at different lateral positions in reciprocal space Q x . We used X-rays tuned to the Fe L3 resonance energy, with the scattering plane aligned along a principal symmetry axis of the array. Details of the specular Δ hysteresis curve are discussed, following the system magnetization from an initial demagnetized state. The periodic structure gives rise to distinct peaks at in-plane reciprocal Bragg positions, as shown by fitting Σ(Q x ) to a model based on a simple unit cell structure. Diffraction order-dependent hysteresis in Δ is observed, indicative of the reordering of magnetization on the system's two interpenetrating sublattices, which markedly deviates from an ideal Ising picture under strong applied fields.