Fermi-Liquid and Nonfermi-Liquid Properties in Weakly Hybridized 4f Intermetallic Compounds

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9624778 Beyermann This project is an experimental investigation of predictions of theories based on an antiferromagneticaly coupled spin-spin interaction between the electrons. The project is divided into three parts. The first part deals with the low-temperature thermodynamic and transport properties in prasedymium systems where the lowest crystal electric-field level of the localized 4f electrons has only quadrupolar, rather than magnetic, internal degrees of freedom. The evolution of the correlated-electron ground state in weakly hybridizing prasedymium intermetallic compounds is studied in the second part. The last part seeks to determine how the renormalized ground state at low temperatures changes under the influence of an applied magnetic field large enough to suppress the magnetic Kondo interaction. This part of the research will be conducted at the National High Magnetic Field Laboratory using pulsed magnetic fields up to 50 T. The results are expected to provide an important understanding of the correlations associated with the low-temperature hybridization of magnetic and quadrupolar states with the conduction electrons. %%% The PI investigates the magnetic and electrical properties of rare earth-intermetallic systems with unusual ground states. Correlated electron behavior in praseodymium-intermetallic compounds will be studied. Praseodymium is uniquely positioned to act as a logical intermediary between the strongly hybridizing cerium and the purely trivalent heavier rare earths. The observation of this behavior in certain systems with unique crystal-electric-field ground states would indicate a new interaction between the 4f orbitals and the conduction electrons. Applied magnetic fields also significantly effect these ground states, the low-temperature properties will be investigated using pulsed fields that are large enough to greatly modify the correlated behavior. This project is a collaboration between three investigators at three different institutions. Sample preparation and basic characterization will be performed at Ames Laboratory. Once suitable compounds are made, they will be sent to UC Riverside for low field magnetic and electrical measurements down to ~50 mK and to the National High Magnetic Field Laboratory at Los Alamos for high-field measurements up to 50 T. ***