Design of self-organized nanostructures to achieve high blocking temperatures in MgO-based d 0 ferromagnets
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We present a materials design of MgO-based d 0 ferromagnets with a high blocking temperature (T B ) based on multiscale simulations. The chemical pair interactions between the N atoms in Mg(O,N) and the Mg vacancies (VMg) in (Mg,VMg)O were calculated using a generalized gradient approximation, and Monte Carlo simulations of the crystal growth were performed to predict the configurations of the dopant distribution. Our simulations showed that self-organized nanostructures could be formed both in Mg(O,N) and (Mg,VMg)O, which suggests that a high T B can be obtained in these d 0 ferromagnets due to the superparamagnetic blocking phenomenon. Furthermore, depending on the crystal growth conditions, it was shown that various self-organized nanostructures, such as three-dimensional nanoclusters and one-dimensional nanowires, could appear.
KeywordsSelf-organization Superparamagnetism d0 ferromagnetism First-principles calculation Monte Carlo simulation Magnesium oxide
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