Heterostructures*

The strong correlation of charge, lattice, spin and orbital degrees of freedom in manganites provides a rich phase diagram for La_1-xSr_xMnO₃ (LSMO) that ranges from canted antiferromagnetism (AFM) to ferromagnetism (FM) to paramagnetism (PM). Here we report the growth of self-assembled (La_0.67Sr_0.33MnO₃/La_0.73Sr_0.27MnO₃/SrTiO₃) thin-film heterostructures that show unusual magnetic properties like exchange bias, spontaneous magnetic reversal and inverted hysteresis, with substantial suppression of octahedral tilts in La-poor region. Using first-principles calculations, we provide a theoretical understanding of the correlation of structural and magnetic properties observed in these self-assembled heterostructures and complement the experiments. We address the following three questions: (I) How does change of x in La_1-xSr_xMnO₃ affect magnetism? (II) What is the origin of the observed exchange bias? and (III) How do we explain the suppression of octahedral tilts in La_0.67Sr_0.33MnO₃ identified as critical for the novel magnetic properties?.