Magnetism in f -electron superlattices

Abstract

We analyze antiferromagnetism in $f$ electron superlattices. We show that the competition between the Kondo effect and the RKKY interaction in $f$ electron materials is modified by the superlattice structure. Thus, the quantum critical point which separates the magnetic phase and the Fermi liquid phase depends on the structure of the $f$ electron superlattice. The competition between the Kondo effect and the RKKY interaction is also reflected in the magnetic interlayer coupling between different $f$ electron layers. We demonstrate that in the case of weak Kondo effect the magnetic interlayer coupling behaves similar to other magnetic heterostructures without Kondo effect. However, close to the quantum phase transition, the dependence of the interlayer coupling on the distance between the $f$ electron layers is modified by the Kondo effect. Another remarkable effect, which is characteristic for $f$ electron superlattice, is that the magnetic interlayer coupling does vanish stepwise depending on the distance between different $f$ electron layers. As a consequence, the quantum critical point depends also stepwise on this distance.