part 5

Magnetic Entropy

Magnetic entropy of ion can be described twofold:

thermodynamic entropy:
(calculated from- scific heat Cmol(T) )

statistical entropy:

kB= 1,38 · 10 -23 J/K (Boltzmann constant)
Statistical entropy, calculated from the number of possible microscopic states (W) that a system of atoms could occupy, consistent with its macroscopic state. In this meanning value of entropy provide information about number of occupied states of single ion in given temperature.

see: EXAMPLES

• Details of Theory

  • Hamiltonian
  • Fine electronic structure Ei, Γi Ei, Γi(|LSLzSz>)
  • The thermodynamic functions

  Computable properties:

  • entropy S(T)
  • specific heat Cmol(T)
  • magnetic moment and influence of the external magnetic field for it m(B,T)
  • magnetic susceptibility along different crystal directions χi(T)
  • visibility of the energy levels in spectroscopy <Γi|J_|Γj>, <Γi|J+|Γj> , <Γi|JZ|Γj>
  • spin and orbital momenta of the magnetic ion in solid <Γi|L|Γi>, <Γi|S|Γi>