Neutron powder diffraction study of NaMn2O4 and Li0.92Mn2O4: Insights on spin-charge-orbital ordering
Artikel i vetenskaplig tidskrift, 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.


N. Matsubara

Kungliga Tekniska Högskolan (KTH)

E. Nocerino

Kungliga Tekniska Högskolan (KTH)

K. Kamazawa

Comprehensive Research Organization for Science and Society (CROSS)

O. K. Forslund

Kungliga Tekniska Högskolan (KTH)

Yasmine Sassa

Chalmers, Fysik, Materialfysik

L. Keller

Paul Scherrer Institut

V. V. Sikolenko

Joint Institute for Nuclear Research (JINR)

Karlsruher Institut für Technologie (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

Kungliga Tekniska Högskolan (KTH)


2643-1564 (eISSN)

Vol. 2 4 043143


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