Intersublattice molecular-field coefficient

Then, we can write the relation between the macroscopic intersublattice molecular-field coefficient /irt and the microscopic exchange parameter Zrt as... 

The first two terms represent the anisotropy energies of the R and T sublattices, respectively. The third term describes the R-T exchange interaction with the intersublattice molecular-field coefficient rt. The last term represents the Zeeman energy in an external field. The equilibrium positions of Af r and Mi can be obtained by minimizing eq. (42) with respect to 0r,0r. However, due to the complexity of this equation, this has to be carried out numerically. 

Here, mrr and krco are the molecular field coefficients representing the interactions between 4f moments and the R-Co intersublattice interactions, respectively. 

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