Anisotropic transport properties of NpPd5Al2

The anisotropic superconductor NpPd 5 Al 2 with the ZrNi 2 Al 5 -type tetragonal structure was studied by means of electrical resistivity and Hall effect in the normal state. The temperature dependence of electrical resistivity ρ ( T ) shows a large anisotropic behavior. The resistivity for J ||[001] is larger than that for J ||[100] in the whole temperature region. At high temperatures p ( T ) is proportional to − log T , which is characteristic behavior in Kondo effect. The field dependence of Hall resistivity ρ H shows a linear dependence up to 55 kOe with a large slope for the field. The slope of ρ H for field along c -axis is negative, but for field along a -axis, the slope dramatically changed from negative to positive with increasing temperature.