[en] A high-resolution scanning superconducting quantum interference device microscopy study of tetragonal single-layer Ti₂Ba₂CuO_6+δ films, deposited on tricrystal SrTiO₃ substrates, demonstrates the effect of spontaneously generated half flux quanta. This observation shows that in addition to YBa₂Cu₃O₇, the order parameter symmetry in TI₂Ba₂CuO_6+δ is consistent with that of a d_x2_-y2 pair state. This result also rules out any bilayer or twinning effects and any pairing that is incompatible with the fourfold rotational symmetry as in the Ti₂Ba₂CuO_6+δ superconducting system. 18 refs., 5 figs

[en] In this note we consider the geometrical effects of a percolating system on the nonlinear transport properties in a superconductor-normal conductor nonlinear resistor network. For realistic composites, the nonlinearity may play an important role in the electrical transport phenomena. A typical example consists of studying a nonlinear composite medium in which an inclusion with nonlinear current-field (J-E) characteristics is randomly embedded in a host with either linear or nonlinear J-E response. For such a system, substantial progress in studies of the effective nonlinear response has been made in the past few years

No abstract available

[en] The effective properties of composites whose structure includes nanocontacts between bulk-phase macrocrystallites are considered. A model for such a nanostructured composite is constructed. Effective values of the thermoelectric power, thermal and electrical conductivities, and thermoelectric figure of merit are calculated in the mean-field approximation.

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No abstract available

[en] Electrical resistivity, thermoelectric power and Hall coefficient have been measured for an antiferromagnetic heavy fermion compound Ce₇Ni₃. Above 30 K the magnetic resistivity ρ_m has a logarithmic temperature dependence -ln T and the large value of ρ below the Neel temperature T_N=1.8 K indicates that the magnetic state below T_N is gap-type antiferromagnetic. For the thermoelectric power, the large negative peak due to magnetic contribution appears at 5 K, vanishes by slight substitution of La for Ce, and the positive peak due to Kondo contribution appears. The temperature dependence of the Hall coefficient R_H above and below 30 K is explained with the skew scattering model and with the anomalous velocity model, respectively. (orig.)

[en] It is shown that the fractal dimension of Sierpinski gasket as a conductor is different from that for its geometry. The fractal dimension of Sierpinski gasket can be defined as D = D_Ε + iD_R. D_Ε and D_R are the fractal dimensions determined from its conductance and resistance, respectively. For 2-d Sierpinski gasket D_R = 3.8 and D_Ε = 1/D_R = 0.263, while for 3-d Sierpinski tetrahedron D_R = 2.41 and D_Ε = 0.415. (author). 4 refs, 5 figs

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[en] A new resistive mode is shown to exist in rotating plasma columns. The mode is localized in the neighbourhood of the radius where the angular velocity of the bulk plasma is equal to minus half the local angular velocity of the ions. This singular point is caused by the Hall term in the generalized Ohm law. The growth rate of the mode scales with eta sup(1/2), where eta is the plasma resistivity. (Author)