Browsing by Author "Martin, Thomas J."
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Item Law and Disorder: Special Stacking Units—Building the Intergrowth Ce₆ Co₅ Ge₁₆(American Chemical Society, 2019-04-22) Felder, Justin B.; Weiland, Ashley; Hodovanets, H.; McCandless, George T.; Estrada, Tania G.; Martin, Thomas J.; Walker, Amy V.; Paglione, J.; Chan, Julia Y.; 0000-0003-4434-2160 (Chan, JY); 0000-0002-2528-1967 (Felder, JB); 0000-0001-7198-3559 (Weiland, A); 0000-0003-2114-3644 (Walker, AV); Felder, Justin B.; Weiland, Ashley; McCandless, George T.; Estrada, Tania G.; Martin, Thomas J.; Walker, Amy V.; Chan, Julia Y.A new structure type of composition Ce₆ Co₅ Ge₁₆ was grown out of a molten Sn flux. Ce₆ Co₅ Ge₁₆ crystallizes in the orthorhombic space group Cmcm, with highly anisotropic lattice parameters of α = 4.3293(5) Å, b = 55.438(8) Å, and c = 4.3104(4) Å. The resulting single crystals were characterized by X-ray diffraction, and the magnetic and transport properties are presented. The Sn-stabilized structure of Ce₆ Co₅ Ge₁₆ is based on the stacking of disordered Ce cuboctahedra and is an intergrowth of existing structure types including AlB₂ , BaNiSn₃, and AuCu₃. The stacking of structural subunits has previously been shown to be significant in the fields of superconductivity, quantum materials, and optical materials. Herein, we present the synthesis, characterization, and complex magnetic behavior of Ce₆ Co₅ Ge₁₆ at low temperature, including three distinct magnetic transitions. © 2019 American Chemical Society.Item One-Dimensional Tellurium Chains: Crystal Structure and Thermodynamic Properties of PrCuₓTe₂ (x ~ 0.45)(Elsevier Inc., 2018-10-20) Baumbach, Ryan; Balicas, Luis; McCandless, Gregory T.; Sotelo, Paola; Zhang, Qiu R.; Evans, Jess; Camdzic, Dino; Martin, Thomas J.; Chan, Julia Y.; Macaluso, Robin T.; 0000-0003-4434-2160 (Chan, JY); McCandless, Gregory T.; Martin, Thomas J.; Chan, Julia Y.X-ray diffraction, crystal structure, magnetization, and heat capacity results are presented for the rare earth chalcogenide ternary system PrCu₀.₄₅Te₂ and its non-4⨍ analogue LaCu₀.₄₀Te₂. The crystal structure of PrCu₀.₄₅Te₂ is characterized by chains of edge and corner-sharing CuTe₄ tetrahedra and Pr centered in polyhedra comprised of Cu and Te. The Cu site is partially occupied and exhibits signatures of local disorder. Magnetic susceptibility measurements show a Curie-Weiss temperature dependence consistent with a Pr³⁺ state. No magnetic ordering is observed down to 1.8 K, but the negative Curie-Weiss temperature suggests an antiferromagnetic exchange interaction. Importantly, the low temperature heat capacity of PrCu₀.₄₅Te₂ is strongly enhanced by comparison to LaCu₀.₄₀Te₂, suggesting that there is a build-up of entropy that is associated with the 4f-electrons from the Pr³⁺ ions. These features reveal possible spin frustration behavior and introduce this family of materials as a template for studying new phenomenon.