纳米金属镝的传导电子定域化

Localization of conduction electrons in nanometer metal Dy

研究不同粒径的稀土金属镝(Dy)纳米晶块体材料的电阻率随温度的变化.电阻率包括剩余电阻率ρres=ρ(0)、磁散射电阻率ρmag(T)和声子散射电阻率ρpho(T).样品的平均粒径分别为10,30,100和1000nm.实验发现磁散射电阻率ρmag(T)和声子散射电阻率ρpho(T)随温度升高而变大.样品电阻率的测量值在(0.8—252)×10-8Ω·m范围,体现出类金属的特征.实验还发现平均粒径为10nm的样品的剩余电阻率ρ(0)约为98.6×10-8Ω·m,比其他样品的剩余电阻率大一个数量级,这是无序化使电子能带变窄出现带尾和定域化电子的实验例证.

The Changes of resistivity with temperature of bulk nanocrystalline metal dysprosium samples with different grain sizes were studied in this paper. The value of the resistivity is a sum of the residual rsistivity ρres = ρ （0）,magnetic scatter resistivity ρmag（T） and phonon scatter resistivity ρpho（T）. The mean grain sizes are 10 nm,30 nm,100 nm and 1000 nm. It was experimentally found that the magnetic scatter resistivity ρmag（T） and phonon scatter resistivity ρpho（T） increase as temperature increases. The measured values of the resistivities of the four samples are in the range of （0. 8—252） × 10-8 Ω·m,representing metalloid features. Experiments also showed that the residual rsistivity ρ （0） of the sample with 10nm mean grain size is about 98. 6 × 10-8 Ω·m,which is about one order of magnitude greater than those of the other three samples. This is an experimental example of the energy band narrowing and the appearance of electron localization with the increase of disorder degree.