Phase separation enhanced magneto-electric coupling in La_(0.7)Ca_(0.3)MnO_(3)/BaTiO_(3) ultra-thin films

We study the origin ofthe magnetoelectric coupling in manganite films on ferroelectric substrates. We find large magnetoelectric coupling in La_(0.7)Ca_(0.3)MnO_(3)/BaTiO_(3) ultra thin films in experiments based on the converse magnetoelectric effect.The magnetization changes by around 30–40% upon applying electric fields on the order of 1kV/cm to the BaTiO_(3) substrate, corresponding to magnetoelectric coupling constants on the order of α=(2–5)·10−7 s/m. Magnetic anisotropy is also affected by the electric field induced strain, resulting in a considerable reduction of coercive fields.We compare the magnetoelectric effectin pre-poled and unpoled BaTiO_(3) substrates. Polarized neutron reflectometry reveals a two-layer behavior with a depressed magnetic layer of around 30Å atthe interface. Magnetic force microscopy (MFM) shows a granular magnetic structure of the La0.7Ca0.3MnO3.The magnetic granularity of the La_(0.7)Ca_(0.3)MnO_(3) film and the robust magnetoelastic coupling at the La_(0.7)Ca_(0.3)MnO_(3)/BaTiO_(3) interface are at the origin of the large magnetoelectric coupling, which is enhanced by phase separation in the manganite

Phase separation enhanced magneto-electric coupling in La0.7Ca0.3MnO3/BaTiO3 ultra-thin films

We study the origin of the magnetoelectric coupling in manganite films on ferroelectric substrates. We find large magnetoelectric coupling in LaCaMnO/BaTiO ultra-thin films in experiments based on the converse magnetoelectric effect. The magnetization changes by around 30-40% upon applying electric fields on the order of 1 kV/cm to the BaTiO substrate, corresponding to magnetoelectric coupling constants on the order of α = (2-5)·10 s/m. Magnetic anisotropy is also affected by the electric field induced strain, resulting in a considerable reduction of coercive fields. We compare the magnetoelectric effect in pre-poled and unpoled BaTiO substrates. Polarized neutron reflectometry reveals a two-layer behavior with a depressed magnetic layer of around 30 Å at the interface. Magnetic force microscopy (MFM) shows a granular magnetic structure of the LaCaMnO. The magnetic granularity of the LaCaMnO film and the robust magnetoelastic coupling at the LaCaMnO/BaTiO interface are at the origin of the large magnetoelectric coupling, which is enhanced by phase separation in the manganite.The authors acknowledge financial support from the Spanish MICINN and MINECO through grants MAT2011-27470-C02-01, MAT2011-27470-C02-02, MAT2014-52405-C2-2-R, MAT2014-52405-C2-1R and CSD-2009-00013