Identifier

etd-09022009-100408

Degree

Doctor of Philosophy (PhD)

Department

Chemistry

Document Type

Dissertation

Abstract

The focus of this dissertation is the structure-property relationships of ternary intermetallic stannides and gallides. We are interested in these compounds because of the wide range of physical properties they possess. While investigating the Ln-Co-Sn system (Ln = lanthanide), we have synthesized single crystals that crystallize in the Yb3Rh4Sn13, Ho7Co6Sn23 and the Tb5Rh6Sn18 structure types. We observe the formation of a particular structure type depending on the size of the lanthanide present. The aforementioned compounds all contain CoSn6 trigonal prisms, which create voids occupied by Ln and Sn polyhedral units. We have also investigated the physical properties of these compounds to correlate the magnetic and transport phenomena observed. To determine the role of magnetic transition metals in lanthanide gallium compounds we have explored the Ln-Fe-Ga system and synthesized single crystals of Ln4FeGa12 (Ln = Y, Tb, Dy, Ho and Er). The structure consists of iron octahedra and face sharing rare-earth cuboctahedra (LnGa3). Magnetic susceptibility measurements performed on Yb4FeGa12 show magnetic ordering in the Fe octahedra, a feature not observed in the isostructural analogues with Tb, Dy, Ho and Er. We have also synthesized single crystals of YbCoGa5 using gallium flux. YbCoGa5 adopts the HoCoGa5 structure type which is made up of CoGa2 and YbGa3 structural units. The synthesis of YbCoGa5 has filled a void in the LnCoGa5 compounds by reported Yuri Grin. We have also studied the single crystal structures of Ni1-xCoxGa2S4 (x = 0, 0.2, 0.3, 0.5) and Ni0.9Mn0.1Ga2S4 to confirm composition and to study the role of doped Co and Mn in the two-dimensional antiferromagnet NiGa2S4.

Date

2009

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

Chan, Julia Y.

Included in

Chemistry Commons

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