Rare Earth Geometrically Frustrated Magnets

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****Technical**** The goal of this research program is to investigate rare earth geometrically frustrated magnets. These are materials in which the interactions between the moments associated with rare earth ions compete with each other due to the particular geometry of the magnetic sublattice. The frustration in these materials leads to unusual low temperature states in which the interaction energies cannot all be simultaneously minimized, such as spin liquids and spin ices. The research will explore new geometrically frustrated magnetic materials and will have a special focus on the spin ice states in which exotic monopole-like excitations have been observed. The experiments will focus on magnetic susceptibility studies but will also include a number of other techniques. The research will be conducted in close collaboration with material scientists and chemists who can provide unique and important samples of new materials. Students involved in the research will participate in traditional and cutting edge training in a wide range of experimental techniques that will prepare them for careers in academe, industry or government.****Non-technical****This is a research program into the physics of a group of materials known as rare earth geometrically frustrated magnets. The magnetic atoms in these materials are unable to direct their magnetic axes (known as the magnetic moments) in a unique way to minimize the combined energy of their collective state. The underlying cause of this inability to minimize the energy is the geometrical arrangement of the magnetic atoms within the materials, and this geometrical arrangement makes these materials excellent models for a wide range of other complex systems which are similarly 'frustrated'. In particular, this research program will probe the nature of special materials known as spin ices, in which the disorder of the magnetic moments mimics the behavior of frozen water and acts as an ideal model system for testing basic understanding of collective behavior of many other systems. The research will also probe other new materials in this class obtained through substituting different elements in the chemical formulae, and looking for various novel behavior that they often exhibit. Understanding these magnetic materials has implications for other systems as diverse as superconducting junction arrays and glasses, and may also provide insight into computational algorithms. The principal investigator has an extensive record of working with a diverse students and involving graduate students and undergraduates in every stage of the research process. Students involved in this research program will participate in traditional and cutting edge training in a wide range of experimental techniques that will prepare them for careers in academe, industry or government.