Resistivity Of Nanostructured Al-Ni Alloys At Low Temperature

Al-Ni alloys are widely used in electron device due to their low density,high melting point,good oxidation resistance and corrosion resistance.With the increasingly miniaturization of electronic devices,their basic structure has reached the nano-scale,many classical theories in the nano-size range will no longer be applicable,the properties of nanostructured materials in mechanics,electricity,magnetism,acoustics and other physical properties are very different from coarse crystal materials The electrical properties of electronic devices play an important role in the function of electronic devices.Therefore,the study on the resistance characteristics of nanostructured Al-Ni alloys is of great significance for their applications in electronic circuits.In magneto-electronics,the resistivity of the material can be changed by adding an external magnetic field to control the spin state of the electron.The resistivity of magnetic materials is obviously different from that of non-magnetic materials because of spinning electron.Therefore,it is of great academic significance to study the electron transport process of non-magnetic metals added with magnetic metals.Nanostructured Al-Ni alloy powders and Al-Ni alloy thin films were prepared by self-suspension directional flow method and magnetron sputtering method,and their crystal structures and morphologies were analyzed by means of SEM,TEM and XRD.The resistivity of Al-Ni alloy in the range of 8-300k was measured by four-probe method.Research results show that:?1?In the high temperature region?100-300 k?,the resistance is mainly derived from the phonon-electron scattering,and the resistivity is proportional to temperature.Due to electron-grain boundary/surface scattering,the temperature dependent resistivity of unsintered nanostructured aluminum at low temperature?8-40 k?show T^2.5 and T⁴ law.The temperature dependent electrical resistivity is a function of T³ and T⁴ for annealing aluminum because of the weaker surface-electron scattering.?2?Due to electron-magneton scattering,the temperature dependent electrical resistivity show function T^1.5 law at high temperature,which same as the coarse crystalline nickel.At low temperature,the temperature dependent resistivity showed T² and T⁴ law due to magneon-electron scattering and phonon-electron scattering.?3?The magnetism of nanostructured Ni₃Al-Ni and NiAl-Ni changed from paramagnetism to weak ferromagnetism in the vicinity of Curie temperature,and the fractional change in electrical resistivity appeared at change temperature,indicating that the resistivity was related to its magnetism.The nanostructured Ni₃Al-Ni and NiAl-Ni also show T² and T⁴ law at low temperature.?4?Nanostructured Al-Ni alloy films prepared by magnetron sputtering are amorphous films.The amorphous films are transformed into single-oriented crystal films when annealing at250°C,and the resistivity transformed from semiconductor properties to metal properties.The resistivity of Al_0.6Ni_0.4 film shows metal features at high temperature and semiconductor feature at low temperature.