Nonlinear I-V characteristics observed in annealed Ni-Fe-Zr metallic glass

Five to seven centimeters long ribbons of Ni0.11Fe0.27Zr0.62 metallic glass were sealed inside quartz ampoules under vacuum and annealed at 973 K for periods varying from 1 to 24 h. The temperature dependence of the electrical resistivity of the annealed samples had been investigated over the temperature range 25-285 K. The annealed samples for less than 6 h displayed insulating electrical behavior like at temperatures below 100 K, while samples annealed for more than 6 h showed metallic behavior like. Nonlinear current-voltage (I-V) characteristics were also observed below 100 K for the less than 6 h annealed samples, while samples annealed for more than 6 h displayed ohmic behavior. These results are quite interesting considering the fact that we only deal with Ni-Fe-Zr metallic alloy and the only factor we change is the annealing period.