Perpustakaan Digital ITB

Perovskite crystals like LaMnO3 (LMO) have interesting characteristic for devices application such as colossal magneto resistance efect, half-metallicity,and resistivity change by imposed magnetic feld. In order to create LMO with graphene based spin valve device, we study the electronic and magnetic properties of cubic LMO with Sr impurity by employing DFT+U method, we consider the strong Coulomb correlation in order to get correct energy gap near Fermi level. In this work we discuss the efect of impurity composition in La1_rxSrxMnO3 (LSMO) system and also the diference between cubic and orthorhombic unit cell. We found that for 12.5%, 25%, 50% of Sr impurity, the LSMO systems has half-metalic ferromagnetic state. System with less Sr impurity have more stable configuration, and the biggest total magnetic moment with 3.85 B is achieved in La0:875Sr0:125MnO3 composition. With less Sr impurity, the magnetic moment and the energy gap will be greater. We also found that the energy gap of minority spin in cubic crystal model is smaller than the orthorhombic model.