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Full-Text Articles in Physics
Spatial And Temporal Correlations Of Xy Macro Spins, Robert Streubel, Noah Kent, Scott Dhuey, Andreas Scholl, Steve Kevan, Peter Fischer
Spatial And Temporal Correlations Of Xy Macro Spins, Robert Streubel, Noah Kent, Scott Dhuey, Andreas Scholl, Steve Kevan, Peter Fischer
Robert Streubel Papers
We use nano disk arrays with square and honeycomb symmetry to investigate magnetic phases and spin correlations of XY dipolar systems at the micro scale. Utilizing magnetization sensitive X-ray photoemission electron microscopy, we probe magnetic ground states and the “order-by-disorder” phenomenon predicted 30 years ago. We observe the antiferromagnetic striped ground state in square lattices, and 6-fold symmetric structures, including trigonal vortex lattices and disordered floating vortices, in the honeycomb lattice. The spin frustration in the honeycomb lattice causes a phase transition from a long-range ordered locked phase over a floating phase with quasi long-range order and indications of a …
Self-Organized Criticality In Sheared Suspensions, L. Corté, Sharon J. Gerbode, W. Man, D. J. Pine
Self-Organized Criticality In Sheared Suspensions, L. Corté, Sharon J. Gerbode, W. Man, D. J. Pine
All HMC Faculty Publications and Research
Recent studies reveal that suspensions of neutrally buoyant non-Brownian particles driven by slow periodic shear can undergo a dynamical phase transition between a fluctuating irreversible steady state and an absorbing reversible state. Using a computer model, we show that such systems exhibit self-organized criticality when a finite particle sedimentation velocity vs is introduced. Under periodic shear, these systems evolve, without external intervention, towards the shear-dependent critical concentration ϕc as vs is reduced. This state is characterized by power-law distributions in the lifetime and size of fluctuating clusters. Experiments exhibit similar behavior and, as vs is reduced, …