Pages

October 24, 2010

Real-space observation of emergent magnetic monopoles and associated Dirac strings in artificial kagome spin ice

Nature Physics - Real-space observation of emergent magnetic monopoles and associated Dirac strings in artificial kagome spin ice

Magnetic monopoles have been predicted to occur as emergent fractional quasiparticles inside pyrochlore spin ice, a frustrated magnetic insulator. Experimental signatures of such emergent monopoles accompanied by Dirac strings have been detected by means of neutron scattering in reciprocal space in pyrochlore spin ice at sub-Kelvin temperatures, but their real-space observation has remained elusive. Here we report on direct, real-space observations of emergent monopoles and their associated Dirac strings in two-dimensional (2D) artificial kagome spin ice at room temperature using synchrotron X-ray photoemission electron microscopy. Magnetization reversal proceeds through the nucleation and avalanche-type dissociation of monopole–antimonopole pairs along 1D Dirac strings. This is in sharp contrast to conventional domain growth in 2D systems, providing a striking example of dimensional reduction due to frustration. The observed hysteresis, monopole densities and 1D Dirac-string avalanches are quantitatively explained by Monte Carlo simulations.




Supplemental information pdf

If you liked this article, please give it a quick review on ycombinator, or Reddit, or StumbleUpon. Thanks

Featured articles

Ocean Floor Gold and Copper
   Ocean Floor Mining Company


Thank You
blog comments powered by Disqus