Spin fluctuations DLM picture

One way forward from this point is to carry out calculations of Q ( e ) for a selection of configurations ( spin spirals, two impurities in a ferromagnet, magnetically ordered superceUs, etc.) by making some assumptions about the most dominant fluctuations. One then fits the set of Q ( e ) s to a simple functional form. Typically a classical Heisenberg model, Q ( e ) = is set up 

We consider a collinear magnetic system magnetized with reference to a single direction n at a temperature T. (A non-collinear generalization can be made by making the notation more complicated.) The orientational probability distribution is denoted by p( ( e ), and its average for a lattice site i, 

The average alignment of fhe local moments, proportional to the magnetization, is 

Using Eqs. (74) and (76), this is shown to be equivalent to solving the equation of state 

The CPA determines an effective medium through which the motion of an electron mimics the motion of an electron on the average. In a system magnetized 

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