Neutron powder diffraction study of NaMn2O4 and Li0.92Mn2O4: Insights on spin-charge-orbital ordering
Journal article, 2020

High-pressure synthesized quasi-one-dimensional NaMn2O4 and Li0.92Mn2O4 are both antiferromagnetic insulators. Here their atomic and magnetic structures are investigated using neutron powder diffraction. The present crystal structural analyses of NaMn2O4 reveal that a Mn3+/Mn4+ charge-ordering state exists even at low temperature (down to 1.5 K). It is evident that one of the Mn sites shows a strongly distorted Mn3+ octahedron due to the Jahn-Teller effect. Above T-N = 35 K, a two-dimensional short-range correlation is observed, as indicated by asymmetric diffuse scattering. Below T-N, two antiferromagnetic transitions are observed: (i) a commensurate long-range Mn3+ spin ordering below T-N1 = 35 K and (ii) an incommensurate Mn4+ spin ordering below T-N2 = 11 K. Surprisingly, the two antiferromagnetic orders are found to be independent of each other. The commensurate magnetic structure (k(C) = 0.5, 0.5, 0.5) follows the magnetic anisotropy of the local easy axes of Mn3+, while the incommensurate Mn4+ one shows a spin-density-wave or a cycloidal order with k(IC) = (0, 0, 0.216). For Li0.92Mn2O4, on the other hand, the absence of a long-range spin-ordered state is confirmed down to 1.5 K.

Author

N. Matsubara

Royal Institute of Technology (KTH)

E. Nocerino

Royal Institute of Technology (KTH)

K. Kamazawa

Comprehensive Research Organization for Science and Society (CROSS)

O. K. Forslund

Royal Institute of Technology (KTH)

Yasmine Sassa

Chalmers, Physics, Materials Physics

L. Keller

Paul Scherrer Institut

V. V. Sikolenko

Joint Institute for Nuclear Research (JINR)

Karlsruhe Institute of Technology (KIT)

V Pomjakushin

Paul Scherrer Institut

H. Sakurai

National Institute for Materials Science (NIMS)

Jun Sugiyama

Comprehensive Research Organization for Science and Society (CROSS)

M. Mansson

Royal Institute of Technology (KTH)

Physical Review Research

26431564 (ISSN)

Vol. 2 4 043143

Subject Categories

Inorganic Chemistry

Other Physics Topics

Condensed Matter Physics

DOI

10.1103/PhysRevResearch.2.043143

More information

Latest update

4/21/2023