Magnetism of a nucleus-electron complex system

Abstract

An effective Hamiltonian is derived for nuclei in the system where each ion has singlet electronic ground state and is interacting with neighboring ions by exchange interaction. This proves again that the enhancement factor for the nuclear Curie temperature is ${(1-\eta )}^{-1\mathrm{}}$ instead of ${(1-\eta )}^{-2\mathrm{}}$, $\eta$ being proportional to the exchange interaction.