Abstract The single phase polycrystalline TbNiC2 sample was obtained by annealing at 1073 K. The compound adopts structure of CeNiC2-type, confirmed by XRD Rietveld refinement: space group Amm2, a = 3.6000(2) A, b = 4.5129(2) A, c = 6.0563(3), RB(I) = 3.72%, Rp = 5.46%. The orthorhombic CeNiC2 crystal structure prototype is shown to be derived from the hexagonal AlB2 one (space group P6/mmm) following the Barnighausen formalism via translationengleiche. Zero-field heat capacity measurements of TbNiC2 in the range of 1.9–300 K reveal Sommerfeld coefficient γ = 8(1) mJ mol−1 K−2, phonon coefficient β = 1.18(1)∙10−4 J mol−1 K−4 with the derived Debye temperature of ΘD ≈ 404 K and antiferromagnetic state below TN = 25 K with a spin-wave excitation gap of Δ = 26(2) K. The 4f-electron contribution to the magnetic entropy change indicates a doublet ground state for a non-Kramer's Tb3+ ion. Thermopower and electrical resistivity of TbNiC2 have been measured in the range of 310–855 K and reveal values characteristic for metallic systems. Seebeck coefficient decreases with increasing temperature approximately linearly in the all studied interval, and its sign changes from positive to negative one at ~660 K, whereby the electrical resistivity increases from 310 K reaching maximum at ~640 K and afterwards decreases slightly. Maximum power factor value of 27 μW m−1 K−2 has been observed at 310 K.

中文翻译：

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TbNiC2 的热容量和高温电传输特性

摘要 通过 1073 K 退火得到单相多晶 TbNiC2 样品。该化合物采用 CeNiC2 型结构，经 XRD Rietveld 精修证实：空间群 Amm2, a = 3.6000(2) A, b = 4.5129(2) A, c = 6.0563(3)，RB(I) = 3.72%，Rp = 5.46%。斜方晶 CeNiC2 晶体结构原型被证明是从六方 AlB2 一（空间群 P6/mmm）通过 Translationengleiche 遵循 Barnighausen 形式主义推导出来的。TbNiC2 在 1.9-300 K 范围内的零场热容测量显示 Sommerfeld 系数 γ = 8(1) mJ mol−1 K−2，声子系数 β = 1.18(1)∙10−4 J mol−1 K −4，导出的德拜温度为 ΘD ≈ 404 K，反铁磁态低于 TN = 25 K，自旋波激发间隙为 Δ = 26(2) K。4f 电子对磁熵变的贡献表明非克莱默 Tb3+ 离子的双基态。TbNiC2 的热电势和电阻率已在 310-855 K 范围内进行测量，并揭示了金属系统的特征值。在所有研究的区间内，塞贝克系数随着温度的升高大致呈线性下降，其符号在~660 K 处从正变为负，其中电阻率从 310 K 增加到~640 K 处达到最大值，然后略有下降。在 310 K 处观察到的最大功率因数值为 27 μW m-1 K-2。在所有研究的区间内，塞贝克系数随着温度的升高大致呈线性下降，其符号在~660 K 处从正变为负，其中电阻率从 310 K 增加到~640 K 处达到最大值，然后略有下降。在 310 K 处观察到的最大功率因数值为 27 μW m-1 K-2。在所有研究的区间内，塞贝克系数随着温度的升高大致呈线性下降，其符号在~660 K 处从正变为负，其中电阻率从 310 K 增加，在~640 K 处达到最大值，然后略有下降。在 310 K 处观察到的最大功率因数值为 27 μW m-1 K-2。