On the change of electronic states at the Fermi level by Ce doping in the intermetallic LaRu2

Variation of electronic structure at the Fermi level in superconducting LaR u2 intermetallic system has been studied by ri-lay absorption near edge str ucture (XANES) spectroscopy, The high resolution Ru K-edge XANES have been measured by fluorescence yield method using multi-element solid state detec tor assembly allowing to reach a signal to noise ratio of the order of Delt a alpha/alpha similar to 10(-4). The results show that a doping by mixed va lence Ce in place of La in the LaBu2 directly modifies the electronic state s at the Fermi level leading to a decrease of the superconducting transitio n temperature, (C) 2001 Elsevier Science B.V. All rights reserved.