Vanishing RKKY interactions in Ce-based cage compounds.

We report the results of thermodynamic measurements in external magnetic field of the cubic Ce-based cage compounds CeCd(= Ni,Pd). Our analysis of the heat-capacity data shows that the Γdoublet is the ground state multiplet of the Ceions. Consequently, for the Γdoublet it can be theoretically shown that the Ruderman-Kittel-Kasuya-Yosida interaction between the localized Ce moments mediated by the conduction electrons, must vanish at temperatures much lower than the energy separating the ground state doublet from the first excited Γquartet.

Non-Fermi liquid regimes with and without quantum criticality in Ce(1-x)Yb(x)CoIn5.

One of the greatest challenges to Landau's Fermi liquid theory--the standard theory of metals--is presented by complex materials with strong electronic correlations. In these materials, non-Fermi liquid transport and thermodynamic properties are often explained by the presence of a continuous quantum phase transition that happens at a quantum critical point (QCP). A QCP can be revealed by applying pressure, magnetic field, or changing the chemical composition.

Elasticity of lyotropic chromonic liquid crystals probed by director reorientation in a magnetic field.

Using a magnetic Frederiks transition technique, we measure the temperature and concentration dependences of splay K1, twist K2, and bend K3 elastic constants for the lyotropic chromonic liquid crystal sunset yellow formed through noncovalent reversible aggregation of organic molecules in water. K1 and K3 are comparable to each other and are an order of magnitude higher than K2. At higher concentrations and lower temperatures, K1 and the ratios K1/K3 and K1/K2 increase, which is attributed to elongation of self-assembled lyotropic chromonic liquid crystal aggregates, a feature not found in conventional thermotropic and lyotropic liquid crystals formed by covalently bound units of a fixed length.

Strong magnetic fluctuations in a superconducting state of CeCoIn5.

We show results on the vortex core dissipation through current-voltage measurements under applied pressure and magnetic field in the superconducting phase of CeCoIn{5}. We find that as soon as the system becomes superconducting, the vortex core resistivity increases sharply as the temperature and magnetic field decrease. The sharp increase in flux-flow resistivity is due to quasiparticle scattering on critical antiferromagnetic fluctuations.

Evidence for vortices in the pseudogap region of Y1-xPrxBa2Cu3O7 from angular magnetoresistivity measurements.

In-plane angular magnetoresistivity Deltarho(anis)(ab) measurements were made on Y(1-x)Pr(x)Ba(2)Cu(3)O(7-delta) single crystals in the pseudogap region. For x>/=0.2 single crystals, Deltarho(anis)(ab)(theta) displays a deviation from the typical quasiparticle contribution (proportional, sin((2)theta) for temperatures smaller than a certain value T(phi) in the pseudogap region.