Local atomic order, electronic structure and electron transport properties of Cu-Zr metallic glasses

Abstract

The basic polyhedral clusters, the optimum glass formers, and the composition-structure-property (glass-forming ability) correlation in Cu-Zr metallic glasses J. Appl. Phys. 107, 063508 (2010) We studied atomic and electronic structures of binary Cu-Zr metallic glasses (MGs) using combined experimental and computational methods including X-ray absorption fine structure spectroscopy, electrical resistivity, thermoelectric power (TEP) measurements, molecular dynamics (MD) simulations, and ab-initio calculations. The results of MD simulations and extended X-ray absorption fine structure analysis indicate that atomic order of Cu-Zr MGs and can be described in terms of interpenetrating icosahedral-like clusters involving five-fold symmetry. MD configurations were used as an input for calculations of theoretical electronic density of states (DOS) functions which exhibits good agreement with the experimental X-ray absorption near-edge spectra. We found no indication of minimum of DOS at Fermi energy predicted by Mott's nearly free electron (NFE) model for glass-forming alloys. The theoretical DOS was subsequently used to test Mott's model describing the temperature variation of electrical resistivity and thermoelectric power of transition metal-based MGs. We demonstrate that the measured temperature variations of electrical resistivity and TEP remain in a contradiction with this model. On the other hand, the experimental temperature dependence of electrical resistivity can be explained by incipient localization of conduction electrons. It is shown that weak localization model works up to relatively high temperatures when localization is destroyed by phonons. Our results indicate that electron transport properties of Cu-Zr MGs are dominated by localization effects rather than by electronic structure.We suggest that NFE model fails to explain a relatively high glass-forming ability of binary Cu-Zr alloys. V C 2014 AIP Publishing LLC.[http://dx

Structure of the glass-forming metallic liquids by ab-initio and classical molecular dynamics, a case study: Quenching the Cu60Ti20Zr20 alloy

“…A quite similar behavior for Cu-Zr binaries is shown in figure (4) of Ref. 86. This shows that the variation with system size is of the same amplitude as the variation between two configurations having the same number of particles.…”

Detecting Structural Features in Metallic Glass via Synchrotron Radiation Experiments Combined with Simulations

“…Because ZrCu is a typical binary alloy system, it enables the formation of MG, revealing the structural mechanisms for its glass formation that have drawn intense interest that a number of theoretical or experimental works have been published [14][15][16][40][41][42][43]. Therefore, it is necessary to compare the present work with previous work in terms of studying methods and structural information.…”

On the impact of global interactions on the structure of metallic glasses

“…Experimentally photo-electron spectroscopy (PES) as well as inverse photo-electron spectroscopy (IPES) are necessary to obtain the exact shape of the DOS in the vicinity of F . If, for example, F is not located in the centre of the pseudogap and only PES results are considered, it may appear that F is mistakenly related to the aforementioned maximum below the pseudogap and not to the pseudogap itself leading to contradictory assumptions about the presence of resonance [36,37].…”