Large dielectric response to the paramagnetic-ferromagnetic transition (T_(C) ~ 100 K) in multiferroic BiMnO_(3) epitaxial thin films

Abstract

The dielectric properties of multiferroic BiMnO_(3) 50 nm epitaxial thin films grown on Nb-doped SrTiO_(3)(001) substrates were analyzed by impedance spectroscopy between 55 and 155 K. One single intrinsic thin film dielectric relaxation process was deconvoluted from an extrinsic electrode interface contribution by the use of an equivalent circuit. The paramagnetic-ferromagnetic transition (T_(C) ~ 100 K was reflected by a large peak in the thin film relative dielectric permittivity. The weak dielectric response at T_(C) observed previously in BiMnO_(3) polycrystals is largely enhanced in thin films. Intrinsic noninsulating thin film resistivity below T_(C) was detected.