Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 54: Magnetic Coupling Phenomena

MA 54.4: Vortrag

Freitag, 20. März 2015, 10:15–10:30, EB 301

Unusual ferromagnetic YMnO₃ phase in YMnO₃/La_2/3Sr_1/3MnO₃ heterostructures — •Carmine Autieri and Biplab Sanyal — Department of Physics and Astronomy, Uppsala University, Box-516, SE-75120 Uppsala, Sweden

By means of ab-initio density functional calculations in the Hubbard model framework, we have studied the structural, magnetic and electronic properties of YMnO₃/La_2/3Sr_1/3MnO₃ heterostructures. Although in the bulk the ground state of YMnO₃ is a ferroelectric antiferromagnet, the YMnO₃/La_2/3Sr_1/3MnO₃ heterostructure stabilizes the ferromagnetic phase in YMnO₃ in the interface region. The hypothetical ferromagnetic phase of bulk YMnO₃ is dielectric and due to substantial differences between the lattice constants in the ab plane, a strong magnetocrystalline anisotropy is present. This anisotropy produces a high coercivity of the unusual ferromagnetic YMnO₃ that can explain the large vertical shift in the hysteresis loops observed in recent experiments. The correlation between weak exchange bias and vertical shift in hysteresis loops is proposed, which calls for reinvestigation of various systems showing vertical shifts.