part 8

An external magnetic field splits the degenerate CEF levels, changes their energy and mixes wave functions of different states. The Cartesian components of the magnetization M are then as follows:

The magnetic susceptibility for any magnetic field can be calculated as δMα/δBα .

where:
α= x, y, z.
μB– Bohr magneton
gL=gj= Lande factor
kB= 1,38 x 10 -23 J/K (Boltzmann constant)

The analytical solution of this equation for small field has the form:

see: EXAMPLES

Details of Theory

• Hamiltonian
• Fine electronic structure 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>