تقرير
Dipolar-coupled moment correlations in clusters of magnetic nanoparticles
| العنوان: | Dipolar-coupled moment correlations in clusters of magnetic nanoparticles |
|---|---|
| المؤلفون: | Bender, Philipp, Wetterskog, Erik, Honecker, Dirk, Fock, Jeppe, Frandsen, Cathrine, Moerland, Christian, Bogart, Lara K., Posth, Oliver, Szczerba, Wojciech, Gavilán, Helena, Costo, Rocio, Fernández-Díaz, Maria Teresa, González-Alonso, David, Barquín, Luis Fernández, Johansson, Christer |
| المصدر: | Phys. Rev. B 98, 224420 (2018) |
| سنة النشر: | 2018 |
| المجموعة: | Condensed Matter |
| مصطلحات موضوعية: | Condensed Matter - Mesoscale and Nanoscale Physics |
| الوصف: | Here, we investigate the nature of the moment coupling between 10-nm DMSA-coated magnetic nanoparticles, in both colloidal dispersion and in powder form. The individual iron oxide cores were composed of > 95% maghemite and agglomerated to clusters. At room temperature the ensemble behaved as a superparamagnet according to M\"ossbauer and magnetization measurements, however, with clear signs of dipolar interactions at low temperatures. Analysis of temperature-dependent AC susceptibility data in the superparamagnetic regime indicates a tendency for dipolar coupled anticorrelations of the core moments within the clusters. To resolve the directional correlations between the particle moments we performed polarized small-angle neutron scattering and determined the magnetic spin-flip cross-section of the powder in low magnetic field at 300 K. We extract the underlying pair distance distribution function of the magnetization vector field by an indirect Fourier transform of the cross-section, and which suggests positive as well as negative correlations between nearest neighbor moments, with anticorrelations clearly dominating for next-nearest moments. These tendencies are confirmed by Monte Carlo simulations of such core-clusters. Comment: 11 pages, 6 figures |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1103/PhysRevB.98.224420 |
| الوصول الحر: | http://arxiv.org/abs/1803.01747Test |
| رقم الانضمام: | edsarx.1803.01747 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1103/PhysRevB.98.224420 |
|---|