Abstract
Substituting Eu by Ca in ferromagnetic leads to a percolation limited magnetic ordering. We present and discuss magneto-optical data of the series, based on measurements of the reflectivity from the far infrared up to the ultraviolet, as a function of temperature and magnetic field. Via the Kramers-Kronig transformation of we extract the complete absorption spectra of samples with different values of . The change of the spectral weight in the Drude component by increasing the magnetic field agrees with a scenario based on the double-exchange model, and suggests a crossover from a ferromagnetic metal to a ferromagnetic Anderson insulator upon increasing Ca content at low temperatures.
- Received 6 October 2005
DOI:https://doi.org/10.1103/PhysRevLett.96.016403
©2006 American Physical Society