AlNi纳米合金薄膜低温电阻率的特性研究

Resistivity of AlNi Nanosized Alloy Film at Low Temperature

通过磁控溅射制备了AlNi纳米合金薄膜,并利用自制的直排四探针低温测量系统测量了薄膜电阻率随温度(8~300K)的变化规律。结果表明:由于电子-声子和电子-磁子相互作用,纯Al和Ni纳米晶薄膜的电阻率分别呈现出正的电阻率温度系数,且电子-磁子散射对电阻率的贡献主要体现在高温区(80~300K),在低温区(<40K)电子-晶界/表面散射对电阻率的贡献占主导地位。Ni原子掺入量的增加,诱导了纳米晶薄膜无序程度的增强,从而使Al1-xNix纳米合金薄膜逐渐由晶体的金属特性过渡到半导体特性,导致其呈现出负的电阻率温度系数。由于增强的电子极化效应,Al1-xNix纳米合金薄膜电阻率与温度的关系并不完全遵循半导体的热激发导电模型。

AlNi films were grown by magnetron sputtering and the change rule of film resistivity with temperature（8-300 K）was measured by self-made straight four-probe low temperature measurement system.It is found that the resistivity of pure Al and Ni nano films exhibits a positive resistivity temperature coefficient due to the electronphonon or electron-magnetron interaction.Moreover,the electron-magnetron scattering plays a much important role at high temperature region（80-300 K）,while the grain boundary/surface has a dominant effect on the resistivity of pure metal films at low temperature region（40K）.With increasing the amount of Ni atoms doping into thefilms,Al1-xNix nano-alloy films gradually transfer from the crystalline-metal phase to semiconductor one with a negative resistivity temperature coefficient.At low temperatures,the electrons are excited from one localize state to another one with the help of phonons.Due to the low-dimensional localization effect,the resistivity-temperature relationship of the Al1-xNixnano-alloy films follows no longer completely the thermally activated conductive model,but also partially the polarization mechanism.