ELECTRICAL-TRANSPORT IN YNI2-XCUXB2C

We have investigated the normal-state conduction mechanism of the supe rconducting intermetallic compounds, YNi2-xCuxB2C by measuring the ele ctrical resistivity and the thermoelectric power (TEP) of YNi2-xCuxB2C for different Cu concentrations x. The resistivity data show that T-c decreases systematically, and the scattering of electrons by structur al disorder seems to increase upon greater Cu substitution. The TEP ha s a nonlinear temperature dependency, which suggests the modified mixe d-valent character (the mixed-valency and the diffusion contribution). However, the discrepancy between TEP data and the best-fit curve of t he modified mixed-valent character for the underdoped samples at low t emperature indicate that an additional scattering mechanism, such as p honon drag, is involved.