450 / 2019-03-08 14:02:47

Pressure-induced Amorphization in Transition Metal Oxides

High pressure; Amorphization; Metal oxides; Phase transition

全体主题 > High Pressure Physics and Materials Science

Pressure-indcued amorphization (PIA) in the solids has been a subject of intense interest because of its fundamental importance in many fields, including the Earth and planetary sciences, physics, chemistry and material science. PIA and the transition from high density amorphous (HDA) to low density amorphous (LDA) form on decompression have been observed in many classes of materials. The earliest experimental evidence is observed in H2O, which is related to density-driven phase transitions. Recently, similar phenomena have been found in several transition metal oxides, such as TiO2 nanomaterials, Y2O3 nanoparticles, Ta2O5, and so on. Although researchers have paid much efforts in this field, the physical mechanism of PIA is still unclear. Recently, we studied the PIA and physical properties of the amorphous phases in several transition metal oxides (TiO2, VO2, and Nb2O5) by using synchrotron x-ray diffraction, Raman, IR, and electronic measurements. Our results show that both the instability of crystal structure and the size of nanoparticles in these transition metal oxides can contribute to the PIA. In addition, some optical properties and electronic transport behaviors of these novel amorphous materials synthesized by high pressure can be effectively modified by pressure engineering. These results provides a new way to synthesize amorphous materials with novel properties.