The Role of Interactions in Systems of Single Domain Ferrimagnetic Iron Oxide Nanoparticles

Authors Silvio Dutz, Rudolf Hergt

Institute of Photonic Technology, Department Nano Biophotonics, Albert-Einstein-Straße, 9, 07745 Jena, Germany

Е-mail, tel.: 0049 3641 206317, fax: 0049 3641 206139
Issue Volume 4, Year 2012, Number 2
Dates Received 09 March 2012; published online 07 May 2012
Citation Silvio Dutz, Rudolf Hergt, J. Nano-Electron. Phys. 4 No 2, 02010 (2012)
PACS Number(s) 5.50.Tt, 75.75.+a
Keywords Magnetic interactions, Packing density, Coercivity, Magnetic nanoparticles (4) , Magnetite (6) .
Annotation Magnetic nanoparticles are interesting materials for a lot of medical and technical applications. A less experimentally investigated question is the influence of particle packing density on magnetic properties due to magnetic interactions between single particles. For this, magnetic nanoparticles of iron oxides prepared as fine dry powder by laser deposition are investigated with respect to their structural and magnetic properties as function of packing density. The particles are nearly spherically shaped single crystals in the magnetic single domain size range with a mean diameter of 21 nm occasionally exhibiting spinel growth facets. Powders of these particles are diluted by nonmagnetic silicon oxide particles in a range of volume concentrations from 0.2 % up to 68 % of the bulk density of magnetite. The concentration dependence of remanence, coercivity and hysteresis losses is determined by measurements of minor loops in a vibrating sample magnetometer. Results which are discussed in the frame of present theoretical models may be understood in terms of the cubic anisotropy of magnetite distorted by a small uniaxial shape contribution.

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