Interactions antiferromagnetic nanoparticles

A layer of uncompensated spins at the surface is responsible for the ferromagnetic interactions observed at low temperatures in normally antiferromagnetic oxides such as MnO, NiO, and CoO [44,45,805,806]. Evidence for such a behavior can be seen from Fig. 1.10. In this study, the blocking temperature was shown to increase with increase in size for NiO and show the opposite trend for MnO nanoparticles. Nanoparticles of ReOs also turn ferromagnetic, exhibiting hysteresis at low temperatures (see Fig. 4.26) [250]. The... 

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