Resistivity and thermoelectric power of Cu-substituted YNi2−xCuxB2C superconductor

Abstract We measured the electrical resistivity and the thermoelectric power(TEP) of YNi 2−x Cu x B 2 C with different Cu concentration x. The resistivity data show that T c decreases systematically and the scattering of electrons by structural disorder increases upon Cu substitution. The TEP has a nonlinear temperature dependency, which suggests the modified mixed valent character(mixed valency plus diffusion contribution). However, the discrepancy between TEP data and the best-fit curve of the modified mixed valent character for the underdoped samples at low temperature indicates that the additional scattering mechanism, such as phonon drag, is involved.