Understanding particle size and distance driven competition of interparticle interactions and effective single-particle anisotropy

0460558 - FZÚ 2017 RIV GB eng J - Článek v odborném periodiku
Pacáková, Barbara - Mantlíková, Alice - Nižňanský, D. - Kubíčková, Simona - Vejpravová, Jana
Understanding particle size and distance driven competition of interparticle interactions and effective single-particle anisotropy.
Journal of Physics-Condensed Matter. Roč. 28, č. 20 (2016), 1-11, č. článku 206004. ISSN 0953-8984. E-ISSN 1361-648X
Grant CEP: GA ČR(CZ) GA15-01953S
Institucionální podpora: RVO:68378271
Klíčová slova: magnetic nanoparticles * single-particle anisotropy * dipolar energy
Kód oboru RIV: BM - Fyzika pevných látek a magnetismus
Impakt faktor: 2.678, rok: 2016

Magnetic response of single-domain nanoparticles (NPs) in concentrated systems is strongly affected by mutual interparticle interactions. However, particle proximity significantly influences the single-particle effective anisotropy. To solve which of these two phenomena plays a dominant role in the magnetic response of real NP systems, systematic study on the samples with well-defined parameters is required. In our work, we prepared a series of nanocomposites constituted of highly- crystalline and well-isolated CoFe2O4 NPs embedded in an amorphous SiO2 matrix using a single-molecule precursor method. This preparation method enabled us to reach a wide interval of particle size and concentration. We observed that the characteristic parameters of the single-domain state (coercivity, blocking temperature) and dipole-dipole interaction energy (Ed-d) were proportional with each other. Our results are in excellent agreement with the Monte-Carlo simulations of particle growth. Therefore, the concept of modified NP effective anisotropy explains the magnetic response of our concentrated NP systems better than the concept of an energy barrier influenced by nterparticle interactions.
Trvalý link: http://hdl.handle.net/11104/0261644