THEORY OF MAGNETIC INSTABILITIES IN HEAVY FERMION COMPOUNDS

In this paper we calculate the magnetic interactions between f electrons in the heavy fermion compounds using the slave boson approach to the periodic Anderson model. We show that at high temperatures we recover the RKKY interaction between local moments which may produce a magnetic transition with T(N) > T*. At low temperatures there is an additional part to the interaction which acts between the quasi-particles and allows magnetic transitions from within the heavy Fermi liquid state. The magnetic moment in the SDW state can be calculated and the possibility of small magnetic moments is discussed.