Exchange coupling parameters

The width of the distribution in the absence of digging, about 80 mT (a), is too large to be exclusively due dipolar ( 20 mT) and hyperfine-coupling ( 10 mT). The following result suggests that it is due to a distribution of the exchange-coupling parameter J z. 

Table 5 Spin levels (Ei,i = 1 ), /T (in cm. K/mol) values at (in °K) corresponding to maximum anisotropy of the main values of the susceptibility /ii(ii = xx, yy, zz) tensor, /avr[Xav = (l/3)(Xxx + Xyy + Xzz)] and anisotropic D12 and A12 tensor parameters of a Fe -CN-Cu" model complex with and without trigonal Jahn-TeUer distortions from model calculations accounting for the difference of Je and Jb2 exchange coupling parameters (exchange anisotropy) or alternatively, assuming an isotropic Heisenberg exchange (1 = 1e = 1b2)...

The zero-field splitting energy of D = 6 cm exceeds the value of the isotropic coupling parameter J. As follows from the expression for D this arises from the high difference between the exchange coupling parameters J( E) and J( B2), and... 

Fig. 9. Variation of the (intersublattice) exchange coupling parameter J between the nearest neighbors in solid a-02 along some normal coordinates of libration. The labels La and Lb refer to librations around the crystal a and b axes, respectively see Fig. 7. The plus and minus signs denote in-phase and out-of-phase librations of the molecules on different sublattices.

Fig. 2 Variation of the exchange coupling parameter / as a function of the Ni - N - C angle in the case of the Ni - CN - Cr linkage...

For cyanide bridged systems, the prediction of the nature and even the magnitude of the exchange coupling parameters between the different magnetic ions is relatively well established and the behavior of most of the reported molecular clusters follows quite well the simple rules expressed in Sect. 2. These rules have been successfully used to build clusters with relatively high-... 

Ti times between 693 [ts (5.5 K) and 0.55 [ts (11.0 K). The temperature dependence of Tx could be fitted equally well to the equations describing Orbach or Raman processes. The unrealistic obtained exponent value in case of the Raman process led the authors to prefer the Orbach process. The Orbach energy gap was derived to be 57 cm. This energy gap corresponds to the energy of the first excited spin state, which allowed choosing between two sets of exchange coupling parameters that fitted the susceptibility curve equally well. 

Curie temperature (in K), compensation temperature T. (in K) and the exchange-coupling parameter Hrt (10 J) for a number of lanthanide-transition-metal intermetallics... 

---