Magnetic properties and spin structure of MnO single crystal and powder

International Conference on Polarised Neutrons for Condensed Matter Investigations

Sun, X.^1 ; Feng, E.^2 ; Su, Y.^2 ; Nemkovski, K.^2 ; Petracic, O.^1 ; Brückel, T.^1

Jülich Centre for Neutron Science JCNS, Peter Grünberg Institut PGI, JARA- FIT, Forschungszentrum Jülich GmbH, Leo-Brandt Str., Jülich

52425, Germany^1

Jülich Centre for Neutron Science JCNS, Heinz Maier-Leibnitz Zentrum MLZ, Forschungszentrum Jülich GmbH, Lichtenberg Str. 1, Garching

85748, Germany^2

关键词: Ac-susceptibility measurements;    Antiferromagnetics;    Magnetization curves;    Mno nanoparticles;    Polarized neutron diffraction;    Polarized neutron scattering;    Single-crystal and powder;    Single-phase powders;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/862/1/012027/pdf
DOI  :  10.1088/1742-6596/862/1/012027

来源: IOP

【 摘 要 】

Zero field cooled (ZFC)/Field Cooled (FC) magnetization curves of a bulk MnO single crystal show a peculiar peak at low temperatures (∼ 40 K) similar to the low temperature peak observed in MnO nanoparticles. In order to investigate the origin of this peak, the spin structure of a MnO single crystal has been studied and compared with a single phase powder sample using magnetometry and polarized neutron scattering. Both magnetometry and polarized neutron diffraction results confirm the antiferromagnetic (AF) phase transition at the Néel temperature TNof 118 K, in both powder and single crystal form. However, the low temperature peak in the ZFC/FC magnetization curves is not observed in single phase MnO powder. To better understand the observed behavior, ac susceptibility measurements have been employed. We conclude that the clear peak in the magnetic signal from the single crystal originates from a small amount of ferrimagnetic (FiM) Mn2O3or Mn3O4impurities, which is grown at the interfaces between MnO crystal twins.