A frustrated system is one whose symmetry precludes the possibility that every pairwise
interaction (“bond”) in the system can be satisfied at the same time. Such systems are …

Within the past 20 years or so, there has occurred an explosion of interest in the magnetic
behavior of pyrochlore oxides of the type A 2 3+ B 2 4+ O 7, where A is a rare-earth ion and …

The spin ice materials, including Ho 2 Ti 2 O 7 and Dy 2 Ti 2 O 7, are rare-earth pyrochlore
magnets which, at low temperatures, enter a constrained paramagnetic state with an …

Sources of magnetic fields—magnetic monopoles—have so far proven elusive as
elementary particles. Condensed-matter physicists have recently proposed several …

Spin-ice materials are magnetic substances in which the spin directions map onto hydrogen
positions in water ice. Their low-temperature magnetic state has been predicted to be a …

The fluidity of water in confined geometries is relevant to processes ranging from tribology to
protein folding, and its molecular mobility in pores and slits has been extensively studied …

Classical crystallography can determine structures as complicated as multi-component
ribosomal assemblies with atomic resolution, but is inadequate for disordered systems …

The “Coulomb phase” is an emergent state for lattice models (particularly highly frustrated
antiferromagnets), which have local constraints that can be mapped to a divergence-free …

A quantum spin liquid is a state of matter where unpaired electrons' spins, although
entangled, do not show magnetic order even at the zero temperature. The realization of a …

This review is a study of how the idea of spin ice has evolved over the years, with a focus on
the scientific questions that have come to define the subject. Since our initial discovery of …