Electron transport in calcium-based metallic glasses

Abstract

New measurements of the x-ray structure factor, electrical resistivity, and thermopower for Ca-AlGa metallic glasses are reported and compared with our previous measurements for Ca-Al glassy metals. Comparison of results from electronic-structure calculations for CaAl, Ca3A1, CaGa, and Ca3Ga alloys in a dose-packed crystalline structure with experiment indicates that the Ca d band may dominate the electron-transport properties of these glassy metals.

Chemical short-range order and the Meyer - Neldel rule for liquid alloys: AlCa and GaAlCa

“…We note immediately that we see no unusual magnitude for S at any concentration for either liquid ternary alloy system; in particular, S ∼ = 0 for the alloy Ga 25 Al 25 Ca 50 , a concentration close to that for which the amorphous alloy showed an unusually large magnitude [4] (see figure 2). Moreover, we also note that while dS/dx has the same sign for the ternary liquid and the amorphous solid alloys, its magnitude for the liquid alloys is about an order of magnitude smaller.…”

“…It has also been reported [4] that, for amorphous Ga 20 Al 20 Ca 60 (and, to a somewhat lesser extent for Ga 10 Al 30 Ca 60 ), the measured thermopower, S, is unusually large, having a magnitude of about 10 µV • C −1 ; this was hard to understand considering that the components are all simple non-transition metals. In the present study we look for an unusual magnitude for S in the liquid ternary alloy at nearly the same composition.…”

Plasma resonance of binary amorphous and crystalline Al-transition metal alloys: Experiments and ab initio calculations

“…Al 100−x Ca x , on the other hand, fits the systematics found before. This is not surprising, as it is known that d-typical properties occur in Ca-containing systems [35,36], i.e., E F lies inside the d-band, making Ca TM-like, with the according consequences for the plasma resonance.…”

Electronic structure and electron transport properties of amorphous alloys

“…Being stimulated by the first pioneering work by St Amand and Giessen [1], a number of Ca-based amorphous alloys have been synthesized and their atomic and electronic structures have been extensively studied in the past decade [2][3][4][5][6][7][8][9][10]. From the point of view of the electron transport properties, the amorphous Ca-M binary alloys have received particular attention because the resistivity is only about 50 µ cm for M = Mg, whereas it exceeds 400 µ cm for M = Al and Ga [3,4].…”

“…From the point of view of the electron transport properties, the amorphous Ca-M binary alloys have received particular attention because the resistivity is only about 50 µ cm for M = Mg, whereas it exceeds 400 µ cm for M = Al and Ga [3,4]. Naugle et al [5] revealed that the replacement of Al by Ga further increases the resistivity in the Ca-Al-Ga alloys. Mizutani et al [6] studied systematically the Al concentration dependence of the electrical resistivity and electronic specific heat coefficient in the amorphous Ca 70 Mg 30−x Al x and Ca 60 Mg 40−x Al x ternary alloys and discussed a sharp increase in resistivity with increasing Al concentration in terms of a decreasing density of states at the Fermi level.…”