Monopole and Dirac string Dynamics in Spin Ice

  title={Monopole and Dirac string Dynamics in Spin Ice},
  author={Ludovic D. C. Jaubert and Peter C W Holdsworth},
  journal={Bulletin of the American Physical Society},
Magnetic monopoles have eluded experimental detection since their prediction nearly a century ago by Dirac. Recently it has been shown that classical analogues of these enigmatic particles occur as excitations out of the topological ground state of a model magnetic system, dipolar spin ice. These quasi-particle excitations do not lead to a modification of Maxwell's equations, but they do interact via Coulombs law and they are of magnetic origin. In this paper we present an experimentally… 

Magnetic monopole dynamics in spin ice.

The diffusive quasi-particle dynamics of real spin ice materials within the 'quantum tunnelling' regime is modelled with Metropolis dynamics, with the particles constrained to move along an underlying network of oriented paths, which are classical analogues of the Dirac strings connecting pairs of Dirac monopoles.

Dirac Strings and Magnetic Monopoles in the Spin Ice Dy2Ti2O7

Magnetic Monopoles Magnets come with a north and a south pole. Despite being predicted to exist, searches in astronomy and in high-energy particle physics experiments for magnetic monopoles (either

Tunable nonequilibrium dynamics of field quenches in spin ice

Nonequilibrium physics in spin ice is presented as a unique setting that combines kinematic constraints, emergent topological defects, and magnetic long-range Coulomb interactions and establishes spin ice as a laboratory of choice for the study of tunable, slow dynamics.

Magnetic monopole and string excitations in two-dimensional spin ice

We study the magnetic excitations of a square lattice spin ice recently produced in an artificial form as an array of nanoscale magnets. Our analysis, based on the dipolar interaction between the

Emergent magnetic monopole dynamics in macroscopically degenerate artificial spin ice

This work presents the first real-time imaging of emergent magnetic monopole motion in a macroscopically degenerate artificial spin ice system consisting of thermally activated Ising-type nanomagnets lithographically arranged onto a pre-etched silicon substrate.

The Aharanov-Bohm effect, magnetic monopoles and reversal in spin-ice lattices.

This article utilizes phase-imaging method based on the AB effect to study the ordering in a one-model system - that of frustrated spin ice - to understand the ordering processes that occur during a magnetic field reversal cycle.

Emergent magnetic monopoles, disorder, and avalanches in artificial kagome spin ice (invited)

We study artificial spin ice with isolated elongated nanoscale islands arranged in a kagome lattice and solely interacting via long range dipolar fields. The artificial kagome spin ice displays a

Brownian motion and quantum dynamics of magnetic monopoles in spin ice

The results clarify the origin of the relatively high frequency response in spin ice and establish adiabatic susceptibility as a revealing characteristic of exotic spin systems.

Thermal fluctuations in artificial spin ice.

The temperature-induced onset of magnetic fluctuations and excitation populations are shown to depend on the lattice spacing and related interaction strength between islands, providing insight into the design of thermal artificial spin ice arrays where the magnetic charge density and response to external fields can be studied in thermal equilibrium.

Direct observation of magnetic monopole defects in an artificial spin-ice system

Free monopoles have fascinated and eluded researchers since their prediction by Dirac1 in 1931. In spin ice, the bulk frustrated magnet, local ordering principles known as ice rules—two-in/two-out



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.

Zero-point entropy in ‘spin ice’

Common water ice (ice Ih) is an unusual solid—the oxygen atoms form a periodic structure but the hydrogen atoms are highly disordered due to there being two inequivalent O–H bond lengths. Pauling

Spin Ice State in Frustrated Magnetic Pyrochlore Materials

The essential physics of spin ice, as it is currently understood, is described and new avenues for future research on related materials and models are identified.

Dynamical crossover in 'hot' spin ice

The magnetic dynamics of the spin ice material Ho2Ti2O7 in its paramagnetic ('hot') phase have been investigated by a combination of neutron spin echo and ac-susceptibility techniques. Relaxation at

Why spin ice obeys the ice rules.

It is shown that one can construct a model dipole interaction, by adding terms of shorter range, which yields precisely the same ground states, and hence entropy, as the nearest-neighbor interaction.

Magnetic relaxation in rare-earth oxide pyrochlores

A theory of magnetic relaxation is developed for geometrically frustrated three-dimensional magnets that can be described by an antiferromagnetic Ising model. These magnetic materials are exemplified

Dipolar interactions and origin of spin ice in ising pyrochlore magnets

It is suggested that the spin-ice behavior in Ising pyrochlore systems is due to long-range dipolar interactions, and that the nearest-neighbor exchange in Dy2Ti2O7 is antiferromagnetic.

Simulation of electrostatic systems in periodic boundary conditions. I. Lattice sums and dielectric constants

The effective interactions of ions, dipoles and higher-order multipoles under periodic boundary conditions are calculated where the array of periodic replications forms an infinite sphere surrounded

Three-dimensional Kasteleyn transition: spin ice in a [100] field.

The approach to saturated magnetization is, in the low-temperature limit, an example of a 3D Kasteleyn transition, which is topological in the sense that magnetized materials are changed only by excitations that span the entire system.


We report a detailed study of the pyrochlore Ho{sub 2}Ti{sub 2}O{sub 7}, in which the magnetic ions (Ho{sup 3+}) are ferromagnetically coupled with J{approximately}1 K . We show that the presence of