Magnetism in Dilute Alloys
Chaps. 7 and 8 are devoted to the theories of magnetic alloys. We treat in Chap. 7 dilute magnetic alloys in noble-metal matrices. In these systems the long-range magnetic interactions known as the RKKY interactions appear. They cause the spin-glass (SG) state as well as the other ordered states because of the oscillatory interaction in sign and the random distribution of the magnetic impurities. We derive the RKKY interaction from the 2-band model and briefly discuss the properties of the SG. In the dilute limit the system behaves as a magnetic impurity and shows a unique property called the Kondo effects, which cannot be described by a simple perturbation theory. We describe the formation of the singlet state (i.e., the Kondo state) with use of a variational theory and give a brief summary of the Kondo effects. Since both topics in this chapter have been established as independent fields, we do not enter into the details; we merely clarify in this book the basic concepts and where they stand in the metallic magnetism.
KeywordsConduction Electron Anderson Model Magnetic Impurity Local Magnetic Moment Magnetic Alloy
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