Antiferromagnetic order in MnO spherical nanoparticles
- ORNL
- Institut Laue-Langevin (ILL)
- Canadian Neutron Beam Centre, National Research Council, Chalk River Laboratorie
- Forschungszentrum Julich, Julich, Germany
We have performed unpolarized and polarized neutron diffraction experiments on monodisperse 8- and 13-nm antiferromagnetic MnO nanoparticles. For the 8-nm sample, the antiferromagnetic transition temperature T{sub N} (114 K) is suppressed compared to that in the bulk material (119 K), while for the 13-nm sample T{sub N} (120 K) is comparable to that in the bulk. The neutron diffraction data of the nanoparticles is well described using the bulk MnO magnetic structure but with a substantially reduced average magnetic moment of 4.2 {+-} 0.3 {micro}{sub B}/Mn for the 8-nm sample and 3.9 {+-} 0.2 {micro}{sub B}/Mn for the 13-nm sample. An analysis of the polarized neutron data on both samples shows that in an individual MnO nanoparticle about 80% of Mn ions order. These results can be explained by a structure in which the monodisperse nanoparticles studied here have a core that behaves similar to the bulk with a surface layer which does not contribute significantly to the magnetic order.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)
- Sponsoring Organization:
- USDOE Laboratory Directed Research and Development (LDRD) Program
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1016606
- Journal Information:
- Physical Review B, Vol. 83, Issue 21; ISSN 1098--0121
- Country of Publication:
- United States
- Language:
- English
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