Magnetodielectric effect in double perovskite La2CoMnO6 thin films

We report on the magnetodielectric properties of well-ordered epitaxial La2CoMnO6 films. The temperature dependence of the dielectric constant is measured in the 10-10(5) Hz frequency range under applied magnetic fields up to 50 kOe. As temperature is lowered, the dielectric constant decreases in the ferromagnetic regime and approaches a plateau below 100 K. A significant enhancement in the dielectric constant under applied magnetic field is observed only in the ferromagnetic phase regime culminating around the transition temperature, while it is absent in the paramagnetic phase regime. Using Arrott plots, we also demonstrate that these films exhibit a second-order phase transition at their Curie temperature. The observed magnetodielectric characteristics of the films are interpreted using the phenomenological theory. (C) 2007 American Institute of Physics.