Concentration dependence of the density of states in the Pauli paramagnetsYNi5-xCux

The temperature dependence and concentration dependence of the heat capacit y C and surface resistance R-s are measured in the compounds YNi5-xCux (x = 0, 0.1, 0.2, 0.25, 0.6, and 1.25). The measured values of C(x) and R-s(x) are used to determine the concentration dependence of the density of states N(E,x). A maximum is observed on N(E,x) at x = 0.2. The results constitute direct experimental confirmation of the nonmonotonic dependence of N(E,x) that has previously been predicted theoretically. It is found that at certa in values of x the low-temperature heat capacity of the compounds YNi5-xCux increases with decreasing temperature, and the temperature dependence of t he electrical resistance has a minimum at T = 10 K. Below 10 K the temperat ure dependence of the resistance obeys a logarithmic law. (C) 2001 American Institute of Physics.