ABSTRACT
We report the results of thermodynamic measurements in external magnetic field of the cubic Ce-based cage compounds CeT2Cd20(T= Ni,Pd). Our analysis of the heat-capacity data shows that the Γ7doublet is the ground state multiplet of the Ce3+ions. Consequently, for the Γ7doublet 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 Γ8quartet. Our findings provide an insight as to why no long range order has been observed in these compounds down to temperatures in the milliKelvin range.
ABSTRACT
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.
ABSTRACT
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. The strength of magnetic fluctuations below the superconducting transition suggests that magnetism is complementary to superconductivity and therefore must be considered in order to fully account for the low-temperature properties of CeCoIn{5}.
ABSTRACT
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. This deviation is consistent with a flux-flow type contribution to angular magnetoresistivity, indicating the presence of vortexlike excitations above the zero-field critical temperature in the pseudogap region.
