Data from: Advancing the Ca14AlSb11 structure type: Synthesis and characterization of Yb14CdSb11 for thermoelectric applications

Kauzlarich, Susan; Opara, Ivan

doi:10.5061/dryad.9w0vt4brw

Abstract: The ternary phase Yb14CdSb11 has been synthesized using both flux and polycrystalline methods. The crystal structure was determined via single-crystal X-ray diffraction, revealing that it crystallizes in the Ca14AlSb11 structure type (I41/acd space group with unit cell parameters of a = 16.5962(2) Å and c = 22.1346(5) Å, 90 K, Z = 8, R1 = 2.65 %: wR2 = 4.58 %. The polycrystalline form of the compound was synthesized from a stoichiometric reaction of Yb4Sb3, CdSb, Yb, and Sb. The elemental composition was confirmed using scanning electron microscopy and energy-dispersive spectroscopy (SEM-EDS), and phase purity was verified by powder X-ray diffraction (PXRD). Thermoelectric measurements, including resistivity, Seebeck coefficient, thermal conductivity, Hall carrier concentration, and Hall mobility, were conducted from 300 to 1273 K. Yb14CdSb11 exhibited a peak zT = 0.80 at 1150 K. Carrier concentration and Hall mobility ranged from to holescm^-3^ and from 1019 cm²V-¹s-^¹, respectively. This carrier concentration is lower than that reported for the Zn or Mn analogs, leading to a lower thermoelectric figure of merit at high temperatures. However, with appropriate doping, it is expected that this phase should also be a promising p-type candidate for high-temperature energy conversion applications. TechnicalInfo: # Data from: Advancing the Ca14AlSb11 structure type: Synthesis and characterization of Yb14CdSb11 for thermoelectric applications ## Description of the data and file structure ### Files and variables #### File: Dryad_PXRD_data.zip **Description:** Heat capacity, powder x-ray diffraction data for CdSb, Yb4Sb3, and Yb14CdSb11, carrier concentration, mobility, electrical resistivity, Seebeck coefficients, thermal conductivity, and zT for Yb14CdSb11. The zip file entitled Yb14CdSb11_All_Data.zip includes data files with Heat Capacity ("Heat capacity_YbCdSb.dat"), Powder X-ray Diffraction data of the binary precursors ("PXRD CdSb.txt", "PXRD Yb4Sb3.txt", and "PXRD_Yb14CdSb11.txt", and Thermoelectric transport data. **Heat Capacity** Heat capacity measurements of a single crystal were done in a Quantum Design PPMS from 2 K to 300 K. **Powder X-ray Diffraction (PXRD)** PXRD data were collected on each sample using a Bruker zero background holder on a Bruker D8 Eco Advanced employing Cu K∝ radiation (λ = 1.54 Å) with a Ni filter to remove Cu Kβ. **Seebeck Coefficient and Electrical Resistivity** Seebeck, resistivity, and Hall data were collected as a function of temperature under high vacuum at the Jet Propulsion Laboratory (JPL). Resistivity and Hall Van der Pauw measurements were performed with a current of 100 mA and a 0.8 T magnet. Seebeck coefficient was measured using a custom two-probe instrument under a high vacuum. Temperature-dependent Seebeck coefficients, electrical resistivity, and thermal conductivity were fit to six-order polynomials to calculate* zT* values. T (K):** **Temperature in Kelvin; r-fit (mΩ·cm): electrical resistivity; S-fit (µV/K): Seebeck coefficient; L- Lorenz number; K-fit: total thermal conductivity; K_e: electronic thermal conductivity; K_L: lattice (phonon) thermal conductivity; PF: power factor; ZT (dimensionless): thermoelectric figure of merit. **Thermal Conductivity** Thermal diffusivity was measured on densified pellets using laser flash analysis on a Netzsch LFA 475 Microflash under Ar(g) flow. The fully densified pellet was sliced into a thin disk (<1.5 mm) and polished until flat with parallel sides. The density of this disk was measured using Archimedes' method with toluene as the liquid. The heat capacity of Yb14CdSb11 was estimated using an adjusted heat capacity, Cp, based on the experimental heat capacity for Yb14MnSb11 and adjusting for the molecular weight of the Yb14CdSb11 analog: Where MM is the molar mass of the respective compounds. This adjusted heat capacity was employed to give the total thermal conductivity according to the equation: κ = D × Cp × *d* (D = measured diffusivity; Cp = heat capacity adjusted; *d* = the temperature-adjusted density). The coefficient of thermal expansion (CTE) measured for Yb14MnSb11 was also employed. This procedure is consistent with past practice for compounds with the Yb14MSb11, compared to previously published work.

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