Correlating interfacial octahedral rotations with magnetism in (LaMnO3+δ)N/(SrTiO3)N superlattices
Xiaofang Zhai1, Long Cheng2, Yang Liu3
11] Hefei National Laboratory for Physical Sciences at the Microscale, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China [2] Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Abstract:
Lattice distortion due to oxygen octahedral rotations have a significant role in mediating the magnetism in oxides, and recently attracts a lot of interests in the study of complex oxides interface. However, the direct experimental evidence for the interrelation between octahedral rotation and magnetism at interface is scarce. Here we demonstrate that interfacial octahedral rotation are closely linked to the strongly modified ferromagnetism in (LaMnO3+δ)N/(SrTiO3)N superlattices. The maximized ferromagnetic moment in the N=6 superlattice is accompanied by a metastable structure (space group Imcm) featuring minimal octahedral rotations (a(-)a(-)c(-), α~4.2°, γ~0.5°). Quenched ferromagnetism for N<4 superlattices is correlated to a substantially enhanced c axis octahedral rotation (a(-)a(-)c(-), α~3.8°, γ~8° for N=2). Monte-Carlo simulation based on double-exchange model qualitatively reproduces the experimental observation, confirming the correlation between octahedral rotation and magnetism. Our study demonstrates that engineering superlattices with controllable interfacial structures can be a feasible new route in realizing functional magnetic materials.
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