This title appears in the Scientific Report :
2017
Please use the identifier:
http://hdl.handle.net/2128/14256 in citations.
Please use the identifier: http://dx.doi.org/10.1103/PhysRevB.95.134427 in citations.
Magnetism of monomer MnO and heterodimer FePt@MnO nanoparticles
Magnetism of monomer MnO and heterodimer FePt@MnO nanoparticles
We report about the magnetic properties of antiferromagnetic (AF) MnO nanoparticles (NPs) with different sizes (6–19 nm). Using a combination of polarized neutron scattering and magnetometry, we were able to resolve previously observed peculiarities. Magnetometry, on the one hand, reveals a peak in...
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Personal Name(s): | Sun, X. |
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Klapper, A. / Su, Y. / Nemkovski, K. / Wildes, A. / Bauer, H. / Köhler, O. / Schilmann, A. / Tremel, W. / Petracic, O. / Brückel, Th. | |
Contributing Institute: |
Streumethoden; JCNS-2 JCNS-FRM-II; JCNS-FRM-II JARA-FIT; JARA-FIT Streumethoden; PGI-4 |
Published in: | Physical Review B Physical review / B, 95 95 (2017 2017) 13 13, S. 134427 134427 |
Imprint: |
Woodbury, NY
Inst.
2017
|
DOI: |
10.1103/PhysRevB.95.134427 |
Document Type: |
Journal Article |
Research Program: |
Jülich Centre for Neutron Research (JCNS) Materials and Processes for Energy and Transport Technologies Quantum Condensed Matter: Magnetism, Superconductivity Controlling Collective States Controlling Collective States |
Subject (ZB): | |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.1103/PhysRevB.95.134427 in citations.
We report about the magnetic properties of antiferromagnetic (AF) MnO nanoparticles (NPs) with different sizes (6–19 nm). Using a combination of polarized neutron scattering and magnetometry, we were able to resolve previously observed peculiarities. Magnetometry, on the one hand, reveals a peak in the zero-field-cooled (ZFC) magnetization curves at low temperatures (∼25 K) but no feature around the Néel temperature at 118 K. On the other hand, polarized neutron scattering shows the expected behavior of the AF order parameter vanishing around 118 K. Moreover, hysteresis curves measured at various temperatures reveal an exchange-bias effect, indicating a coupling of an AF core to a ferromagnetic (FM)-like shell. ZFC data measured at various fields exclude a purely superparamagnetic (SPM) scenario. We conclude that the magnetic behavior of MnO particles can be explained by a superposition of SPM-like thermal fluctuations of the AF-Néel vector inside the AF core and a magnetic coupling to a ferrimagnetic Mn2O3 or Mn3O4 shell. In addition, we have studied heterodimer (“Janus”) particles, where a FM FePt particle is attached to the AF MnO particle. Via the exchange-bias effect, the magnetic moment of the FePt subunit is stabilized by the MnO. |