"Origin of Pressure-Induced Polyamorphism in Ce75Al25 Metallic Glass"

Qiao-shi Zeng: Yang Ding, Wendy L. Mao, Wenge Yang, Stas. V. Sinogeikin, Jinfu Shu, Ho-kwang Mao, and J. Z. Jiang; Phys. Rev. Lett., 03/11/10.

Additional Authors: Yang Ding, Wendy L. Mao, Wenge Yang, Stas. V. Sinogeikin, Jinfu Shu, Ho-kwang Mao, and J. Z. Jiang

Abstract:

Using high-pressure synchrotron x-ray absorption spectroscopy, we observed the Ce 4f electron in Ce75Al25 metallic glass transform from its ambient localized state to an itinerant state above 5 GPa. A parallel x-ray diffraction study revealed a volume collapse of about 8.6%, coinciding with 4f delocalization. The transition started from a low-density state below 1.5 GPa, went through continuous densification ending with a high-density state above 5 GPa. This new type of electronic polyamorphism in densely packed metallic glass is dictated by the Ce constituent, and is fundamentally distinct from the well-established structural polyamorphism in which densification is caused by coordination change and atomic rearrangement.