Emerging Chirality in Artificial Spin Ice

Abstract

Artificial spin ice, made up of planar nanostructured arrays of simple ferromagnetic bars, is a playground for rich physics associated with the spin alignment of the bars and spin texture associated with the magnetic frustration at the bar vertices. The phase diagram is exotic, showing magnetic monopole-like defects and liquid and solid phases of spins arranged in loop states with predicted chiral order. We show that magnetotransport measurements in connected honeycomb structures yield the onset of an anomalous Hall signal at 50K. The temperature scale can be attributed to the long-range dipolar ice phase.The topological Hall signal arises because chiral loops form at the sample edges, indicating a generic route to exotic states via nanoarray edge structure.

Angular-dependent magnetization reversal processes in artificial spin ice

“…[2][3][4][5][6] Additionally, the patterning of 'artificial spin ice' geometries can give rise to a large number of energetically equivalent states which has been explored in both dipolar coupled systems 7,8 and interconnected networks. 9 Such structures have been suggested for macroscopic studies of fundamental frustrated phenomena and their associated emergent behavior showing strong links to the thermodynamics of the system. 10 The field driven manipulation of pre-existing DWs in connected artificial spin ice systems is governed by the chirality and topological nature of the DW 11,12 and it's time-evolution during dynamic propagation.…”

Complex Ordered Patterns in Mechanical Instability Induced Geometrically Frustrated Triangular Cellular Structures

“…Given the difficulty of probing individual spin states in a system without disrupting their states [4], a number of artificial frustrated systems with individual discrete elements that can be directly monitored have been investigated to understand how spins accommodate the frustration of their interactions. These include artificial spin ice systems [4][5][6][7][8][9][10][11], colloid systems [2,12,13], and periodically arranged magnetic rotors [14]. Since geometrical frustration typically gives rise to disordered configurations, there has been growing interest in investigating mechanisms to generate order in frustrated systems.…”

Emergent geometric frustration of artificial magnetic skyrmion crystals

“…The most studied artificial spin ice systems are created using arrays of nanomagnets with a bistable single-domain magnetization [43,44,[46][47][48][49][50][51][52][53][54][55][56][57][63][64][65][66][67]. Artificial nanomagnet spin ice systems have been realized experimentally for square [43,50,51,56,66], and honeycomb [49,52,68] lattices, each having different analogous features to the naturally occurring rare-earth pyrochlore lattice [37].…”

“…Although the naturally occurring spin ices exhibit interesting types of topological monopole defects and "ice-rule" states [39,40], the frustrated behaviors occur only at very low temperatures and the individual spin ordering or defects cannot be directly visualized on the atomic scale size. Recent advances in nanofabrication technology have permitted the creation of artificial ice systems [43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62] that mimic the behavior of geometrically frustrated atomic spin ices at much larger length scales and higher temperatures, where direct visualization of the microscopic effective spin configurations under controlled conditions is possible.…”