Spatial distribution of hole around LaNiO₃/LaMnO₃ interface

The superlattice of LaMnO₃ and LaNiO₃ exhibits ferromagnetism as a results of charge transfer between Mn and Ni across the interface[1]. In case of bilayer of LaNiO₃ on LaMnO₃(NMT) and of LaMnO₃ on LaNiO₃(MNT) grown on SrTiO₃ (001) substrate, the former shows much larger magnetization [2]. Detailed structure and valence distribution of the interfaces were examined by non-resonant and K-edge resonant surface x-ray diffraction method. Bayesian inference was applied to derive the atomic positions [3] to derive local polarization. The spatial distribution of Mn⁴⁺ was determined from the energy spectra of scattering. As a results, Mn⁴⁺ was found mainly in the Ni-Mn mixture region, and the total amount of transferred electron in NMT(0.8±0.2e^-) is larger than MNT(0.5±0.2e^-), which is consistent with the larger magnetization in NMT.

[1] M. Kitamura et al., Appl. Phys. Lett. 108, 111603 (2016).
[2] M. Gibert et al., Nano. Lett. 15, 7355 (2015).
[3] M. Anada et al., J. Appl. Cryst. 50 1611-1616 (2017).