Ferromagnetic exchange

Fig. 7 Early models for polymers with ferromagnetic exchange behavior.

Figure 10 McConnell s mechanism for ferromagnetic exchange between ion-radicals[115]. At is less than As because of direct exchange involving the degenerate donor orbitals. This results in greater stabilization of the lowest triplet state compared to lowest singlet state upon turning on electron transfer between the donor and acceptor orbitals.

The magnetic moment is given by the difference between the filling of majority and minority spin bands, which is directly related to the ferromagnetic exchange splitting between the bands. There is also an orbital-moment contribution to the moment, but in 3d-based magnets, it is often small due to... 

By fitting the low temperature susceptibility data to a series expansion for the spin-1/2, ID Heisenberg system [49], we find a 1/T2 dependence of the susceptibility which confirms the quasi-ID behaviour and gives a ferromagnetic coupling constant of 50 K. This plot is shown in Fig. 20a. McConnell s mechanism for ferromagnetic exchange... 

The uniform interaction (UI) model assumes that the freeon, Heisenberg ferromagnetic exchange interaction is uniform for all pairs in the sample i. e.,... 

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