This is the first book to present a coherent theoretical and experimental treatment of the rapidly developing field of macroscopic quantum tunneling of the magnetic moment. The theory is based on the concept of the magnetic instanton and its renormalization by the dissipative environment. The book includes discussions of the tunneling of magnetic moment in small ferromagnetic grains, tunneling of the Ne'el vector in antiferromagnetic grains, quantum nucleation of magnetic domains, and quantum depinning of domain walls. The experimental part collects the majority of recent data that are, or...

This book deals with the concepts and techniques that have been developed to meet this challenge and with their application to the interpretation of experiment. The author surveys in detail the many-body techniques, scaling, renormalization group, Fermi liquid and Bethe ansatz, which lead to a solution of the Kondo problem for most of the theoretical models. The book also deals with special techniques for N-fold degenerate models for rare earth magnetic impurities. The many-body techniques developed to deal with strong correlation impurity problems have also been extended to provide a partial...