Snynthesis and Magnetization of BaLn₂O₄ (Ln = Lanthanide)

• Other Authors: Lundberg, Matthew (authoraut)
• Format: Others
• Language: English; English
• Published: Florida State University
• Subjects: Materials science
• Online Access: http://purl.flvc.org/fsu/fd/FSU_migr_etd-9212

The BaLn(sub)2(/sub)O(sub)4(/sub) family has been synthesized successfully as single crystals by the flux-growth method. The phases crystallize in the CaV(sub)2(/sub)O(sub)4(/sub) structure prototype in space group Pnma (# 62). The structure has been studied using single-crystal x-ray diffraction, and stoichiometry confirmed with EDS, and the unit cell parameters and atomic positions have been determined for the whole lanthanide series (with the exception of the Lu compound). The effects of the lanthanide ionic radius on the atomic positions in the unit cell has been studied in terms of fractional atomic coordinates, bond lengths and angles, and bond valence sums. Magnetic measurements have been performed on the series with the exception of the La, Eu, and Lu members in the form of susceptibility versus temperature. The crystals all show signs of geometric antiferromagnetic frustration with the Néel temperatures significantly below the temperature predicted by the Weiss constant. Additionally some members of the family, namely BaCe(sub)2(/sub)O(sub)4(/sub), BaNd(sub)2(/sub)O(sub)4(/sub), BaPr(sub)2(/sub)O(sub)4(/sub), BaSm(sub)2(/sub)O(sub)4(/sub), BaTb(sub)2(/sub)O(sub)4(/sub), and BaYb(sub)2(/sub)O(sub)4(/sub) show significant crystal field splitting, that causes deviation from Currie-Weiss behavior === A Thesis submitted to the Interdisciplinary Program in Materials Science in partial fulfillment of the requirements for the degree of Master of Science. === Summer Semester, 2014. === July 21, 2014. === Includes bibliographical references. === Theo Siegrist, Professor Directing Thesis; Susan Latturner, Committee Member; Sachin Shanbhag, Committee Member.