Dielectric catastrophe at the magnetic field induced insulator to metal transition in Pr1-xCaxMnO3(x = 0.30, 0.37) crystals
Laboratoire CRISMAT, CNRS UMR 6508, ENSICAEN, 6 Bd. du Maréchal Juin, 14050 Caen Cedex, France
Corresponding author: a Bohdan.Kundys@ensicaen.fr
Revised: 16 June 2006
Published online: 7 July 2006
The dielectric permittivity and resistivity have been measured simultaneously as a function of magnetic field in Pr1-xCaxMnO3 crystals with different doping. A huge increase of dielectric permittivity was detected near percolation threshold. The dielectric and conductive properties are found to be mutually correlated throughout insulator to metal transition evidencing the dielectric catastrophe phenomenon. Data are analyzed in a framework of Maxwell-Garnett theory and the Mott-Hubbard theory attributed to the role of strong Coulomb interactions.
PACS: 71.45.Gm – Exchange, correlation, dielectric and magnetic response functions, plasmons / 81.40.Tv – Optical and dielectric properties / 77.80.-e – Ferroelectricity and antiferroelectricity
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2006