RUI: Probing Spin and Charge States in Electron-Correlated Materials by Nuclear Resonance

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Bernal9820631This is an experimental condensed matter physics project that concentrates on the study of intrinsic inhomogeneous structures in electron-correlated materials. The project will characterize both static and dynamic properties of local magnetic-field and electric-field-gradient distributions by means of magnetic- and quadrupolar-resonance techniques. Electron-correlated materials (systems in which the electrons interact strongly with each other resulting in a macroscopic behavior completely different from that displayed by more common non-interacting electron systems, such as normal metals) display richness in behavior as a response to changes in temperature and magnetic field. Examples of such behavior are superconductivity, magnetism, antiferromagnetism, small-moment and quadrupolar ordering, non-Fermi-liquid behavior, and colossal magnetoresistance. The emphasis of the project is on elucidating the role-played by temperature-dependent magnetic inhomogenieties on the intrinsic behavior of non-Fermi-liquid materials and heavy-fermion antiferromagnets, and in characterizing spin and charge structures (stripes) in the lanthanum nickelates. To this end, the project will study stoichiometric heavy-fermion compounds and related alloys, and 61Ni-enriched La2-xSrxNiO4+d. Through the project, training will be achieved of undergraduate and graduate (masters level) students in the techniques of magnetic resonance, radio-frequency electronics, cryogenics, and computer interface. The project 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 is an experimental condensed matter physics project that concentrates on the understanding of electron-correlated 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. Electron-correlated materials are currently the subject of great deal of interest for science and technology. From the scientific point of view, they are interesting because of the richness in behavior they display in response to changes in temperature and magnetic field. Technologically, the properties that have been discovered in these systems, such as superconductivity, and colossal magnetoresistance, make them potential candidates for future applications. The project is a contribution to a wider effort of condensed matter research by the scientific community at the national and international levels. It will deal with the application of nuclear resonance techniques to study the properties of electron distributions in compounds containing uranium and cerium such as the so-called heavy-fermion systems as well as in the lanthanum nickelates. The emphasis is on elucidating the role played by intrinsic inhomogeneous structures that may be forming in these materials as the temperature is decreased. Through the project, training will be achieved of undergraduate and graduate (masters level) students in the techniques of magnetic resonance, radio-frequency electronics, cryogenics, and computer interface. The project will be carried out in collaboration with The University of California, Riverside, The University of Florida, and the Kamerlingh Onnes Lab in the Netherlands.***