Esr experiments on the kondo insulator cenisn

Abstract

Below a characteristic temperature, due to hybridization effects, Kondo insulators exhibit a gap in the electronic density of states and behave like semiconductors. By using (Formula presented) electron spin resonance, the compound (Formula presented) was investigated as a representative of this class. In addition, the metal-to-insulator transition was studied as a function of doping for (Formula presented) and (Formula presented) The linewidth of the Gd resonance yields direct information about the density of states at the Fermi energy. So the size of the gap can clearly be estimated for the pure compound, and the closing of the gap by substitution of Ni by Co or Pt can be followed in detail. These results are compared to measurements of NMR, specific heat, and susceptibility. © 1999 The American Physical Society.