Spin-glass to a ferromagnetic phase

At temperatures Tfield dependence of magnetization has the form of hysteresis loop, as it is shown in Fig. 2.38 of Chap. 2 for the 6 nm particles. Down to the lowest temperatures (around T = 5 K) all the results can be well described without consideration of the particles interaction. It should be emphasized, that superparamagnetic phase exists in the noninteracting nanoparticles ensemble, while their interaction could lead to spin glass state or ferromagnetic phase depending on the particles concentration. As the characteristic feature of hysteresis loop is presence of a remnant magnetization at // = 0, the authors [111] had considered its behavior with the help of the expression... 

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