One of the most important quantities characterizing a magnetic system and its microscopic interactions is the magnetic specific heat C M . In particular, for a paramagnetic system at temperatures much higher than the ordering temperature, the magnetic specific heat can often be expressed as a simple series expansion in 1/T $$ C_M /R = C_2 /T^2 + C_3 /T^3 + ... $$ (1) whose coefficients C 2, C 3, … can be related directly to traces of different powers of the interaction Hamiltonian describing the system (see, e.g., Ref. 1).