By Professor Vladimir A. Gubanov, Dr. Alexandr I. Liechtenstein, Dr. Andrei V. Postnikov (auth.)
The quantum concept of magnetism is a well-developed a part of modern solid-state physics. the fundamental options of this conception can be utilized to explain such very important results as ferromagnetic ordering oflocalized magnetic moments in crystals and ferromagnetism of metals produced by way of basically delocalized electrons, in addition to a number of varieties of mutual orientation of atomic magnetic moments in solids owning assorted crystal lattices and compositions. In contemporary years,the spin-fluctuational technique has been built, which may triumph over a few contradictions among "localized" and "itinerant" types within the quantum mechanics of magnetic crystals. those are just many of the valuable achievements of quantum magnetic idea. just about all of the recognized magnetic houses of solids may be qualitat ively defined at the foundation of its suggestions. extra advancements should still open up the opportunity of trustworthy quantitative description of magnetic homes of solids. regrettably, such calculations in accordance with version techniques seem to be very complex and, often, now not convinced adequate. The relatively small variety of parameters of qualitative types aren't capable of take into consideration the very kinds of magnetic interactions that seem in crystals. additional improvement of magnetic idea calls for quantitative info on digital wave functionality within the crystal thought of. this is proved by way of digital band constitution and cluster calculations. in lots of situations the latter could be a start line for quantitative calculations of parameters utilized in magnetic theory.