Elastic torsion effects in magnetic nanoparticle diblock-copolymer structures
- Schulz, Leander Physik-Department E13, Technische Universität München, Garching, Germany / Dépt de Physique, Université de Fribourg, Switzerland
- Schirmacher, W. Physik-Department E13, Technische Universität München, Garching, Germany - Institut für Physik, Universität Mainz, Germany
- Omran, A. Physik-Department E13, Technische Universität München, Garching, Germany
- Shah, V. R. Nebraska Center for Materials and Nanoscience, University of Nebraska Lincoln, USA
- Böni, P. Physik-Department, E21, Technische Universität München, Garching, Germany
- Petry, W. Physik-Department E13, Technische Universität München, Garching, Germany
- Müller-Buschbaum, P. Physik-Department E13, Technische Universität München, Garching, Germany
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10.08.2010
Published in:
- Journal of Physics: Condensed Matter. - 2010, vol. 22, no. 34, p. 346008
English
Magnetic properties of thin composite films, consisting of non-interacting polystyrene-coated γ-Fe₂O₃ (maghemite) nanoparticles embedded into polystyrene-block-polyisoprene P(S-b-I) diblock-copolymer films are investigated. Different particle concentrations, ranging from 0.7 to 43 wt%, have been used. The magnetization measured as a function of external field and temperature shows typical features of anisotropic superparamagnets including a hysteresis at low temperatures and blocking phenomena. However, the data cannot be reconciled with the unmodified Stoner–Wohlfarth–Néel theory. Applying an appropriate generalization we find evidence for either an elastic torque being exerted on the nanoparticles by the field or a broad distribution of anisotropy constants.
- Faculty
- Faculté des sciences et de médecine
- Department
- Département de Physique
- Language
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- English
- Classification
- Physics
- License
- License undefined
- Identifiers
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- RERO DOC 20622
- DOI 10.1088/0953-8984/22/34/346008
- Persistent URL
- https://folia.unifr.ch/unifr/documents/301758
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