First-principles stabilization of an unconventional collinear magnetic ordering in distorted manganites

Picozzi, S.; Bihlmayer, G.; Yamauchi, K.; Blügel, S.

doi:10.1103/PhysRevB.74.094402

Journal Article

PreJuSER-52566

First-principles stabilization of an unconventional collinear magnetic ordering in distorted manganites

Picozzi, S. ; Yamauchi, K. ; Bihlmayer, G.FZJ* ; Blügel, S.FZJ*

2006
APS College Park, Md.

Physical review / B 74(9), 094402 (2006) [10.1103/PhysRevB.74.094402]

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Please use a persistent id in citations: http://hdl.handle.net/2128/1447 doi:10.1103/PhysRevB.74.094402

Abstract: First-principles calculations have been performed for different collinear magnetic orderings in orthorhombic manganites, such as HoMnO3, TbMnO3, and YMnO3, showing large GdFeO3-like distortions. Our results suggest that the AFM-E type ordering, experimentally observed in HoMnO3 and recently proposed from model Hamiltonian studies, is indeed the magnetic ground state. Its stability is strongly connected with octahedral distortions and points to the relevance of structural more than chemical effects. The calculated exchange constants, extracted from a Heisenberg model used to fit the first-principles total energies, show that the ferromagnetic in-plane nearest-neighbor coupling is reduced compared to less-distorted manganites, such as LaMnO3. In parallel, the antiferromagnetic next-nearest-neighbor coupling along planar Mn-O-O-Mn paths in highly distorted manganites plays a relevant role in the stabilization of the AFM-E spin configuration. In agreement with experiments, the density of states shows that this phase is insulating with an indirect band gap of similar to 0.5 eV.

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