We present a heuristic, semiphenomenological model of the anomalous temperature (T) dependence of resistivity ρxx recently observed experimentally in the quasi-one-dimensional (Q1D) organic conductors of the (TMTSF)2X family in moderately strong magnetic fields. We suggest that a Q1D conductor behaves like an insulator (dρxx/dT < 0), when its effective dimensionality is one, and like a metal (d...

Temperature dependent electrical resistivity, crystal structure and heat capacity measurements reveal a resistivity drop and electrical transport behavior change corresponding to a structural change near 400 K in Ca(3)Co(4)O(9). The lattice parameter c varies smoothly with increasing temperature while anomalies in a, b(1) and b(2) lattice parameters occur near 400 K. The Ca site in the Ca(2)CoO...

We systematically investigated the in-plane resistivity anisotropy of electron-underdoped EuFe2−xCoxAs2 and BaFe2−xCoxAs2, and hole-underdoped Ba1−xKxFe2As2. Large in-plane resistivity anisotropy was found in the former samples, while tiny in-plane resistivity anisotropy was detected in the latter ones. When it is detected, the anisotropy starts above the structural transition temperature and i...

We report the results of angle dependent resistivity of NdFeAsO0.82F0.18 single crystals in the superconducting state. By doing the scaling of resistivity within the frame of the anisotropic Ginzburg-Landau theory, it is found that the angle dependent resistivity measured under different magnetic fields at a certain temperature can be collapsed onto one curve. As a scaling parameter, the anisot...

The unusual temperature dependence of the resistivity and its in-plane anisotropy observed in the Fe-based superconducting materials, particularly Ba(Fe_{1-x}Co_{x})_{2}As_{2}, has been a long-standing puzzle. Here, we consider the effect of impurity scattering on the temperature dependence of the average resistivity within a simple two-band model of a dirty spin density wave metal. The sharp d...

The electrical resistivity and ac magnetic susceptibility of the heavy-fermion compound Ce7Ni3 were measured in the temperature range from 0.4 to 300 K and in the pressure range up to 1.5 GPa. The Néel temperature of 1.9 K for antiferromagnetic transition at ambient pressure decreases with increasing pressure and vanishes at about 0.33 GPa. The magnetic resistivity, rm5r~Ce7Ni3)-r(La7Ni3), decr...

In this paper, we report careful transport and magnetic measurements on single crystals of deuterated k-~ET!2Cu@N~CN!2!#Br. By cooling the sample at different rates, it is found that cooling through 80 K has a dramatic effect on the normal state metal-insulator transition and the superconducting transition temperatures. In-plane resistivity depends strongly on the cooling rate for temperatures ...

Magnetic island equilibria resulting from reconnection in magnetohydrodynamic (MHD) simulations are explored in a two-dimensional slab geometry. Magnetic islands are evolved to finite amplitude with a nonzero resistivity. The resistivity and flows are then set to zero and the system is allowed to relax toward equilibrium. A y-type singular current layer in the equilibrium state is identified fo...

The domain wall ~DW! contribution to magnetoresistance has been investigated using an epitaxial microfabricated bcc ~110! Fe wires of 2 mm linewidth. A strong in-plane uniaxial component to the magnetic anisotropy perpendicular to the wire axis causes a regular stripe domain pattern with closure domains. The stripe domain width in zero-applied magnetic field is strongly affected by the magnetic...

The magnetostructural transitions, magnetocaloric effects, and magnetoresistance properties of Ni45Mn43CrSn11 Heusler alloys were investigated using X-ray diffraction (XRD), field-dependent magnetization, and electrical resistivity measurements. A large inverse and direct magnetocaloric effect has been observed in Ni45Mn43CrSn11 across the martensitic and Curie transition temperature, respectiv...