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Artificial ‘spin ice’ in a geometrically frustrated lattice of nanoscale ferromagnetic islands
This work reports an artificial geometrically frustrated magnet based on an array of lithographically fabricated single-domain ferromagnetic islands, arranged such that the dipole interactions create a two-dimensional analogue to spin ice, behaviour which is strikingly similar to the low-temperature state of spin ice.
Effective temperature in an interacting vertex system: theory and experiment on artificial spin ice.
It is demonstrated that an effective temperature, controlled by an external magnetic drive, describes the microstates of frustrated arrays of interacting single-domain nanomagnets and therefore their full statistical properties.
Demagnetization protocols for frustrated interacting nanomagnet arrays
We report a study of demagnetization protocols for frustrated arrays of interacting single-domain permalloy nanomagnets by rotating the arrays in a changing magnetic field. The most effective
Energy minimization and ac demagnetization in a nanomagnet array.
This work exhaustively resolves every (Ising-like) magnetic degree of freedom in frustrated arrays of single-domain ferromagnetic islands, resulting in a complex disordered magnetic state that can be described by a maximum-entropy ensemble constrained to satisfy just nearest-neighbor correlations.
Ground state lost but degeneracy found: the effective thermodynamics of artificial spin ice.
It is demonstrated that this athermal system has an effective extensive degeneracy and a formalism is introduced that can predict the populations of local states in this icelike system with no adjustable parameters.
Chemically doped double-walled carbon nanotubes: cylindrical molecular capacitors.
A self-consistent tight-binding model confirms the observed molecular Faraday cage effect, i.e., most of the charge resides on the outer wall, even when this wall was originally semiconducting and the inner wall was metallic.
Colloquium: Artificial spin ice : Designing and imaging magnetic frustration
Frustration, the presence of competing interactions, is ubiquitous in the physical sciences and is a source of degeneracy and disorder, which in turn gives rise to new and interesting physical
Crystallites of magnetic charges in artificial spin ice
Here it is demonstrated a method for thermalizing artificial spin ices with square and kagome lattices by heating above the Curie temperature of the constituent material, which achieves unprecedented thermal ordering of the moments.
Emergent ice rule and magnetic charge screening from vertex frustration in artificial spin ice
The shakti lattice describes a new type of frustration not found in naturally occurring materials. Fabrication of the first artificial spin-ice array displaying shakti dynamics confirms the locally
Unhappy vertices in artificial spin ice: new degeneracies from vertex frustration
In 1935, Pauling estimated the residual entropy of water ice with remarkable accuracy by considering the degeneracy of the ice rule solely at the vertex level. Indeed, his estimate works well for