RUI: Probing Hidden Order and Magnetic Disorder in Correlated Electron Systems Using Spin Probes

California State L A University Auxiliary Services Inc., Los Angeles CA

Investigators

Abstract

This individual investigator award will support an experimental project at a predominately undergraduate institution. The project concentrates on the study of intrinsic inhomogeneous structures in correlated electron materials, with a goal of elucidating the nature of phase transitions and the role played by disordered dynamics in the behavior of these systems as the temperature is decreased. Static and dynamic properties of local magnetic-field and electric-field-gradient distributions in systems undergoing phase transitions will be characterized by means of magnetic- and quadrupolar-resonance techniques. In addition, muon spin rotation techniques will be used to characterize and assess the role of disordered dynamics in the ground state of systems displaying characteristics consistent with a quantum critical point. Undergraduate and graduate (masters level) students working on this project will receive training in the techniques of magnetic resonance, radio-frequency electronics, cryogenics, and interfacing computers with experiments. The research will be carried out in collaboration with The University of California, Riverside, The University of Florida, and the Kamerlingh Onnes Lab in the Netherlands. This individual investigator award will support an experimental project at a predominately undergraduate institution. The project concentrates on increasing our understanding of correlated electron materials. These are systems in which the electrons interact strongly with each other, resulting in a behavior completely different from that displayed by the more common non-interacting electron systems such as normal metals. Correlated electron materials are currently the subject of great deal of interest for science and technology due to the wide variety of behaviors they display in response to changes in temperature and magnetic field. These materials may exhibit superconductivity, magnetism, antiferromagnetism, small-moment and quadrupolar ordering, non-Fermi liquid behavior, colossal magnetoresistance or hidden order. Nuclear-magnetic and quadrupolar-resonance and muon spin rotation techniques will be used to study the static and dynamic properties of correlated-electrons in rare-earth and actinide compounds such as heavy-fermion systems. The emphasis is on elucidating the nature of phase transitions and the role played by disordered dynamics in the behavior of these systems as the temperature is decreased. Undergraduate and graduate (masters level) students working on this project will receive training in the techniques of magnetic resonance, radio-frequency electronics, cryogenics, and interfacing computers with experiments. The research will be carried out in collaboration with The University of California, Riverside, The University of Florida, and the Kamerlingh Onnes Lab in the Netherlands.