Measurement of low-temperature transport properties of Cu-based Cu-Zr-Ti bulk metallic glass

Abstract

The transport properties, including electrical resistivity ͑͒, thermopower ͑S͒, and thermal conductivity ͑͒ of bulk metallic glass alloys Cu 64 Zr 28.5 Ti 7.1 , Cu 62.3 Zr 23.7 Ti 10 , Cu 60.6 Zr 26.9 Ti 12.5 and Cu 58.8 Zr 26.2 Ti 15 in the temperature range 10-300 K are reported. The temperature variations of electrical resistivity in these alloys, with a negative temperature coefficient, are found to be rather weak. These findings are consistent with the metallic glass nature of these compounds. It is observed that the electrical resistivity increases with increasing Ti concentration, ascribed to the enhancement of disorder with such a composition change. The magnetoresistivity of Cu 64 Zr 28.5 Ti 7.5 alloy decreases with increasing temperature and increases with increasing magnetic field, suggesting that the weak localization effect dominates the electrical transport. The temperature-dependent thermopower and thermal conductivity characteristics are nearly identical and weakly independent of compositions. It is noted that the observed ͑T͒ of Cu-Zr-Ti metallic glass alloys show notable similarities with the quasicrystalline system. There are two main features in S͑T͒, a knee around 120 K and a plateau below 50 K, which represent the deviation from the expected linear behavior. A detailed theoretical analysis has suggested that the appearance of the knee is due to the electron-phonon interaction at low temperatures and the plateau is associated with low-energy excitations in glasses.

Transport, magnetic and thermal properties of amorphous and crystallized Ce2Ni2Ga ternary gallide

“…One can see that S is linearly decreasing from 0 to 60-70 K to reach a negative value of −2, −3 V/K, above 70 K then S is almost constant. These values are in concordance with those observed in the literature for amorphous metals [33][34][35][36].…”

Structure and electrical properties of nitrided NbN–TiN sol–gel derived films

“…For instance, non-universal power-low temperature dependencies of conductivity r(T) $ T 1/3 and r(T) $ T 1/2 have been shown in amorphous InO x near metal-insulator transition [13]. On the other hand, the resistivity in metallic glasses and A15 compounds could be described by the relation proposed by Mooij [14] for transition metal alloys [15,16]. In this case, the temperature dependence of resistivity may be written as q(T) = q 0 + A(q 0C Àq 0 )T, where q 0 is the residual resistivity, q 0C is the value of residual resistivity for which the temperature coefficient of resistivity changes from negative to positive and A is a coefficient describing the resistivity part that is dependent on temperature.…”

Fabrication and characterization of metallic glasses with a specific microstructure for micro-electro-mechanical system applications

“…The A alloy has a lowest thermal conductivity because the thermal conductivity of La metal is more lower than Cu and Zr metals, and the heat generated is the most difficult to diffuse into the base material, which cause actinomorphic stripes and the largest heat-affected zone size. The B alloy has a medium thermal conductivity of 5.02 Wm À1 K À1 at 300 K [15], and the heat generated can only affect the smaller zone around the hole, while the C alloy has a higher thermal conductivity of 8-10 Wm À1 K À1 at 300 K [16], and the heat can be conduct quickly, thus the least heat-affected zone can be found.…”

“…Three alloy compositions, La 62 Al 14 Ni 12 Cu 12 , Zr 55 Al 10 -Ni 5 Cu 30 and Cu 46 Zr 44 Al 7 Y 3 BMGs were used in the present MEDM study for their differences in thermophysical properties such as melting temperatures and thermal conductivities and so on [10,[15][16][17][18], which are shown in Table 2. During machining of micro-hole, a number of processing-induced defects are typically encountered, including recast layer (re-solidified material around the hole surface), heat-affected zone or micro-cracking, because MEDM is a high temperature process to melt and evaporate the surface material [9].…”