Anomalous compression behaviour in Nd2O3 studied by x-ray diffraction and Raman spectroscopy

• Main Authors: Sheng Jiang, Jing Liu, Ligang Bai, Xiaodong Li, Yanchun Li, Shangming He, Shuai Yan, Dongxu Liang
• Format: Article
• Language: English
• Published: AIP Publishing LLC 2018-02-01
• Series: AIP Advances
• Online Access: http://dx.doi.org/10.1063/1.5018020

The structural stability of hexagonal Nd2O3 under pressure has been investigated by in situ synchrotron angle dispersive x-ray diffraction and Raman spectroscopy up to 53.1 GPa and 37.0 GPa, respectively. Rietveld analysis of the x-ray diffraction data indicate that the hexagonal Nd2O3 undergoes an isostructural phase transition in the pressure range from 10.2 to 20.3 GPa, accompanied by anomalous lattice compressibility and pressure-volume curve. A third-order Birch-Murnaghan fit based on the observed Pressure-Volume data yields zero pressure bulk moduli (B0) of 142(4) and 183(6) GPa for the low and high pressure hexagonal phases, respectively. Raman spectroscopy confirms this isostructural transition, the pressure dependence of the Raman modes display noticeable breaks in the pressure range of 9.7-20.9 GPa, which is consistent with the change of Nd-O bond length. The pressure coefficients of Raman peaks and the mode Grüneisen parameters of different Raman modes were also determined.