Synthesis and Characterization of New Lanthanide Chalcogenides
Type of DegreeDissertation
Chemistry and Biochemistry
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A large number of new ternary and quaternary lanthanide chalcogenides have been synthesized through solid-state reactions of corresponding elements with the aid of alkali metal halides and Sb2Q3 (Q = S, Se) fluxes. Molten Sb2Q3 (Q = S, Se) fluxes have been valuable media for accessing interlanthanide chalcogenides. The structures of these compounds were determined by single crystal X-ray diffraction. Their optical and magnetic properties were characterized by UV-vis-NIR diffuse reflectance spectroscopy, magnetic susceptibility measurements, and Mössbauer spectroscopy. Their structures and physical properties depend highly on the choices of lanthanides and chalcogenides. They have shown a variety of structures including ordered and disordered types under different reaction conditions. Most compounds are semiconductors with wide tunable band gaps. Different magnetic behaviors have been found in these systems, namely Curie-Weiss type paramagnetism, van Vleck paramagnetism, antiferromagnetism, ferromagnetism, and spin glass performance. Possible spin-frustrations in some of these interlanthanide compounds were also discussed.