Dielectric loss of half-doped manganite La_0.5Ca_0.5MnO₃

The dielectric loss tanδ of half-doped manganite La_0.5Ca_0.5MnO₃ is investigated using Green's function technique. The La_0.5Ca_0.5MnO₃ is described by the Kondo-lattice model in the double exchange limit, taking into account the Jahn-Teller distortion and the super-exchange interaction between the localized electrons. It is found that the intensity of tanδ decreases with increasing |ε_JT|, V, and U. It is also observed that the transition temperature T_P rises as |ε_JT| and U increase. It is worth noting that T_P remains unchanged and the strength of tanδ increases with increasing g. The calculated dielectric loss results are explained theoretically, and these behaviors are in qualitative agreement with the experimental results.