Effect of the Sign of Anisotropy Constants on the Properties of the System of Interacting Ferromagnetic Nanoparticles
M. Sadek a, M. Marchwianya,b, M. Woinska c, A. Majhofer a, J. Gosk d, A. Twardowski a and J. Szczytko a
aInstitute of Experimental Physics, Faculty of Physics, University of Warsaw, L. Pasteura 5, 02-093 Warszawa, Poland
bInterdisciplinary Centre for Mathematical and Computational Modelling, University of Warsaw, A. PawiƄskiego 5a, 02-106 Warszawa, Poland
cFaculty of Chemistry, University of Warsaw, L. Pasteura 1, 02-093 Warszawa, Poland
dFaculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warszawa, Poland
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We use the Monte Carlo simulation method to investigate the influence of the signs of magnetocrystalline anisotropy constants and the magnetic dipole-dipole interactions on the zero field cooled-field cooled magnetization experiments and hysteresis curves of a system of magnetic nanoparticles. Positive first cubic anisotropy constant K1 results in larger blocking temperatures and larger coercive fields of a system, while the second anisotropy constant K2 is practically of negligible importance for the phenomena investigated. Magnetic dipole-dipole interactions are important only in the most dense systems of particles and their effects practically disappear for systems where the distance between the closest particles exceeds three particle diameters.

DOI: 10.12693/APhysPolA.129.A-53
PACS numbers: 75.40.Mg, 75.50.Tt, 75.75.-c