Dielectric relaxation and magnetodielectric response in epitaxial thin films of La2NiMnO6

Abstract

Frequency and magnetic field dependent dielectric measurements have been performed on epitaxial thin films of the double perovskite La2NiMnO6, revealing a dielectric relaxation and magnetodielectric effect. The films are grown on Nb-doped and SrRuO3-coated SrTiO3 substrates using the pulsed laser deposition technique. While a rapid dielectric relaxation is observed at ∼300K, the relaxation rate increases dramatically at lower temperatures. Below the Curie temperature of La2NiMnO6, the dielectric constant increases in a magnetic field for a range of temperature. This temperature range depends on magnetic field and measurement frequency. The results are explained by the influence of a magnetic field on the dipolar relaxation.