Pressure-induced phase transition in LaCo_5 studied by x-ray emission spectroscopy, x-ray diffraction, and density functional theory

摘要

The pressure dependences of the electronic and crystal structures of LaCo_5 have been studied with high-resolution x-ray absorption spectroscopy (XAS) and x-ray diffraction comprehensively. The lattice constant ratio of α/c shows an anomaly around 12.18 GPa without change in the lattice symmetry. In the XAS spectra with partial fluorescence mode as well as in the integrated absolute difference values of the Co Kβ emission spectra, a change in the electronic structure was found at around a similar pressure range as the lattice constant anomaly. Density functional theory calculations confirm the presence of a magnetic anomaly around the same pressure region. No temperature dependence of the electronic structure for LaCo_5 and YCO_5 was observed.