Bethe–Slater curve

Bethe–Slater curve: elements above the horizontal axis are ferromagnetic, below the axis are antiferromagnetic

Bethe–Slater curve is a graphical representation of exchange energy for transition metals as a function of the ratio of the interatomic distance a to the radius r of the 3d electron shell.[1]

The curve illustrates why certain metals are ferromagnetic and other antiferromagnetic.

For a pair of atoms, the exchange interaction wij (responsible for the energy E) is calculated as:[2]

w_{ij}= - 2 J_{ex} S_i \cdot S_j

where: J = exchange integral; S = electron spins; i and j = indices of the two atoms.

References

  1. ↑ http://www.nitt.edu/home/academics/departments/physics/faculty/lecturers/justin/students/magnetic/exchange/
  2. ↑ Soshin Chikazumi, Physics of Ferromagnetism, Oxford University Press, New York, 1997, p. 125, ISBN 0-19-851776-9
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