A study of the structural, Raman scattering and thermodynamic properties of a nanocrystalline ceramic rare earth oxide Yb₂O₃ and its bulk counterpart is reported. The nanosized sample was obtained by mechanical milling of bulk Yb₂O₃ (99.998%, high purity powder). The Rietveld analysis of the X-ray diffraction data indicates the presence of nanoparticles with a mean grain size of 12 ± 1 nm after 75 h of milling time. The crystallographic structure within nanoparticles is cubic Ia-3 and the lattice parameter a = 10.455 ± 0.002 Å. The nanocrystalline structure is confirmed by the evaluation of transmission electron microscopy images, showing a size distribution with a mean size D_TEM = 8 ± 2 nm. Measurements of the specific heat (2 K–300 K) reveal an excess contribution respect to the unmilled (bulk) compound in the high temperature region above 70 K. At lower temperatures the results are consistent with a drastic change of the antiferromagnetic contribution (ordered below T_N = 2.2 K) as a result of the magnetic disorder arising from the size reduction process. The specific heat above T_N for the bulk and nanocrystalline samples are explained by the interplay among the phonon contribution, crystalline field and the presence of anharmonic effects. In the nanocrystalline state, broadening and shifts of the contribution of phonon modes to the Raman spectra, and a further reinforcement of the anharmonic contribution are found.

报告了纳米晶陶瓷稀土氧化物 Yb ₂ O ₃及其本体对应物的结构、拉曼散射和热力学特性的研究。通过机械研磨大块 Yb ₂ O ₃（99.998%，高纯度粉末）获得纳米尺寸的样品。X 射线衍射数据的 Rietveld 分析表明，在研磨时间 75 小时后，存在平均粒径为 12 ± 1 nm 的纳米颗粒。纳米颗粒内的晶体结构为立方Ia-3，晶格参数a  = 10.455 ± 0.002 Å。通过透射电子显微镜图像的评估证实了纳米晶体结构，显示了平均尺寸的尺寸分布D _TEM  = 8 ± 2 nm。比热 (2 K–300 K) 的测量结果表明，在高于 70 K 的高温区域中，未研磨（块状）化合物的贡献过多。在较低温度下，结果与反铁磁贡献（有序低于T _N  = 2.2 K），这是由于尺寸减小过程引起的磁无序。T _N以上的比热对于块状和纳米晶体样品，可以通过声子贡献、晶体场和非谐效应的存在之间的相互作用来解释。在纳米晶体状态下，发现声子模式对拉曼光谱的贡献的加宽和偏移，以及非谐波贡献的进一步增强。