Giant dielectric permittivity of electron-doped manganite thin films, Ca1-xLaxMnO3 (0≤x≤0.03) -: art. no. 034102

A giant low-frequency, in-plane dielectric constant, epsilon similar to 10(6), for epitaxial thin films of Ca1-xLaxMnO3 (x less than or equal to 0.03) was observed over a broad temperature range, 4 K less than or equal to T less than or equal to 300 K. This phenomenon is attributed to an internal barrier-layer capacitor (IBLC) structure, with Schottky contacts between semiconducting grains. The room-temperature epsilon increases substantially with electron (La) doping, consistent with a simple model for IBLCs. The measured values of epsilon exceed those of conventional two-phase IBLC materials based on (Ba, Sr)TiO3 as well as on recently discovered CaCu3Ti4O12 and (Li, Ti)-doped NiO. (C) 2005 American Institute of Physics.