ELECTRONIC AND MAGNETIC PROPERTIES OF MIXED-VALENCE SYSTEMS

Abstract

Our aim in this ther•is has been to gain understanding of some aspects of a wide variety of physical properties of the mixed-valence (1W) systems, viz., the valence transitions, T-P phase diagram, magnetic properties and specific heat. The characteristic feature of these systems, such as SmS, SmSe, Smi_xGdxS, UN, CeSn3, YbA13, UNi5..xCux etc., under various ranges of pressure, temperature and composition (x) is the existence of highly correlated atomic like f-electrons, inter-acting and mixing strongly with the less correlated Bloch-like (sd-) electrons. In these materials both,the very heavy f-electrons that obey (to a good approximation) atomic spectral rules,and lighter sd- electrons,coexist at the Fermi surface....