Yusuf Yuksel, Erol Vatansever, Hamza Polat
We have presented dynamic phase transition features and stationary-state behavior of a ferrimagnetic small nanoparticle system with a core-shell structure. By means of detailed Monte Carlo simulations, a complete picture of the phase diagrams and magnetization profiles have been presented. According to N\'{e}el nomenclature, the magnetization curves of the particle have been found to obey N-type, P-type and W-type classification schemes under certain conditions. W-type behavior observed in the present work can be regarded as a novel feature of the dynamic behavior of the magnetic nanoparticle system, since the equilibrium counterpart of the model does not exhibit such kind of phenomenon. Much effort has been devoted to investigation of hysteretic response of the particle and we observed the existence of triple hysteresis loop behavior which originates from the existence of a weak ferromagnetic core coupling $J_{c}/J_{sh}$, as well as a strong antiferromagnetic interface exchange interaction $J_{int}/J_{sh}$. Particular attention has also been paid on the influence of the particle size on the thermal and magnetic properties, as well as magneto-optical features such as coercivity, remanence and compensation temperature of the particle. Furthermore, we have not found any evidence of the first order phase transitions in the present system.
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http://arxiv.org/abs/1207.2023
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