Ferromagnetic behavior

It should be stressed that below a critical (Blocking) temperature (Tg) S.P. clusters will have a slow relaxation time (t) at which their net moment will align so-to-speak "parallel" to H, and thus appear to behave as if they had an apparent "bulk-like" ferromagnetic behavior. This aspect will result in a hysteresis or an "apparent" ferromagnetic behavior. Conversely, above the Tg, the hysteresis will disappear and the clusters will show a unique curve with no hysteresis (Fig. 2). 

Since the reported synthesis [1] of stable 2-phenyl-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide, NitPh, considerable effort has been spent in the physical characterization of nitronyl nitroxide compounds. Their general formula is presented in Figure 1 A. These compounds carry a delocalized, S = 1/2, unpaired electron. Among them, some derivatives were found to be paramagnetic at low temperature (NitPh, [1]), others were found to exhibit an antiferromagnetic or a ferromagnetic behavior [2-7]. 

This problem will be considered on the basis of charge-transfer coordination of organic polynitriles to substituted ferrocenes. The practical significance of the charge-transfer coordinative species (salts) is their ferromagnetic behavior (see Section 8.5). The salts contain the cation-radical and anion-radical counterparts. Peculiarities in electronic structures of the cation-radical parts within the salts are topics of our interest. 

Assume there exists some hypothetical metal that exhibits ferromagnetic behavior and that has a simple cubic structure, an atomic radius of 0.153 nm, and a saturation flux density of 0.76 tesla. Determine the number of Bohr magnetons per atom for this material. 

Ga,Mn)N film prepared by post growth Mn doping using solid state diffusion shows ferromagnetic behavior at room temperature, which is confirmed by the observation of an anomalous Hall effect (Reed et al. 2001). 

V doped ZnO (V composition 0.05-0.15) with higher conductivity shows ferromagnetic behavior at room temperature, whereas that with lower conductivity is nonmagnetic (Saeki etal. 2001). 

There are four important energy terms that affect ferromagnetic behavior ... 

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