Efeitos da dopagem com bário nas propriedades da perovskita dupla La2NiMnO6

Abstract

Multiferroics show coupling between at least two ferroics orders . The rare-earth manganites double perovskite structure are multiferroic materials which have been extensively studied in the last decade since the discovery of the magno capacitance La2NiMnO6 (LNMO). Besides the search for a semiconductor ferromagnetic at room temperature has attracted much attention due to its direct application in Spintronics for development of quantum computers. The LNMO is a semiconductor whose multiferroic ferromagnetic Curie temperature is near room temperature (Tc ~ 280 K), which allows its application in magnetic devices that can be controlled by electric fields. In this work, the dopamos LNMO with different concentrations of barium to investigate the effects on the structural, magnetic and vibrational. The results show that even a small concentration of barium increases the magnetic response due to an increase in structural order and changes the symmetry of LNMO, while the Curie temperature and oxidation states are not changed. Using the results of spin-phonon coupling and infrared spectroscopy we concluded that the structural planning is responsible for increasing the magnetic moment and that the colossal dielectric constant of LNMO is purely extrinsic origin.