Exchange interaction parameter

Working with lanthanide systems offers two major advantages over their 3d counterparts. First, with lanthanide systems, one can deal with relatively concentrated alloys and yet preserve the isolated impurity limit to a good approximation. As we noted in the Introduction (section 1), this is due to the small spatial extent of the 4f wavefunctions (of the order of one-tenth of an interatomic spacing) which implies little direct interaction between neighboring lanthanide ions, and the relatively small magnitude of the exchange interaction parameter (. 0.1 eV). The concentrated systems are discussed in the next section however, it should be emphasized that the anomalies observed in the physical properties of both concentrated and dilute lanthanide systems are qualitatively identical. Hence, one frequently can perform measurements on a... 

The solution thermodynamics is formulated in terms of reduced thermodynamic fxmctions for the mixture. A new parameter similar to the Flory X is introduced X12. To accoxmt for molecules of different size and shape, a site fraction is introduced for intermolecular interactions 0. The polymer is divided into r isometric parts, with size chosen so that one isometric unit corresponds to one solvent molecule. For an oligomeric solvent, more than one isometric unit can be assigned to the solvent. Each isometric unit is characterized by s intermolecular contact sites. Corresponding to each intermolecular contact site there is an energy of interaction -tj. For a two-component liquid mixture, an exchange interaction parameter is defined as ... 

Exchange interaction parameter in a number of pseudo-binary intermetallic (R.YIjCo, and (R,Y)2Co,B3... 

Exchange interaction parameter. n. in a number of pseudo-binary intermetallic R-(T,Al,Si,C) compounds... 

Exchange interaction parameter Agf in a number of the pseudo-binary intermetaliic RT12 compounds ... 

Nuclear magnetic resonance of A1 in the paramagnetic state of R-Al intermetallic compounds. Values of the s-f exchange interaction parameter /sf are based on the uniform polarization model [Jaccarino et al. (I960)]. 

Fermi surface structure, the energy spectrum of the conduction electrons and the s-f exchange interaction parameter which in turn will affect Tc and the characteristics of the helical structure ((p, fcr)- A more thorough discussion of this question will be presented in the next section. 

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