MnAs Nanocrystals Embedded in GaAs
A. Kwiatkowski a, D. Wasik a, M. Kamińska a, A. Twardowski a, P. Dłużewski b, J. Borysiuk c and J. Sadowski b, d
a Institute of Experimental Physics, University of Warsaw, Hoża 69, 00-681 Warsaw, Poland
b Institute of Physics, PAS, al. Lotników 32/46, 02-668 Warsaw, Poland
c Institute of Electronic Materials Technology, Wólczyńska 133, 01-919 Warsaw, Poland
d MAX-Lab, Lund University, 221 00 Lund, Sweden
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Received: 7 06 2008;
Magnetic properties of MnAs nanocrystals embedded in GaAs are analyzed in the frame of phenomenological model proposed by Sasaki for ferritin superparamagnets. Our calculations explain qualitatively experimental data of magnetization versus temperature, obtained according to zero-field-cooled and field-cooled protocols. They show dynamics of magnetization of MnAs nanocrystals in range of temperature from 10 K to 320 K. There is transition from state in which very slow dynamics is observed (frozen state) to state in which dynamics is fast (quasi-superparamagnetic state).
DOI: 10.12693/APhysPolA.114.1207
PACS numbers: 75.20.-g, 75.75.+a