Ternary thin Ni90-xYxAl10 films have been prepared by using cocondensation method under ultrahigh vacuum condition.Films with a wide concentration range between Ni80Y10Al10 and Ni20Y70AI10 were found to be amorphous.W...Ternary thin Ni90-xYxAl10 films have been prepared by using cocondensation method under ultrahigh vacuum condition.Films with a wide concentration range between Ni80Y10Al10 and Ni20Y70AI10 were found to be amorphous.With an addition of 10at.%AI the thermal stability of binary amorphous NiY has been enhanced.This is caused by a more closely packed structure and the bondings between AI and Ni,Y may also play an important role.The surface investigation by scanning tunneling microscopy suggests that the atom redistribution and the crystallization have been limited in the clusters with a size of about 10.5nm.The nanosized amorphous clusters of Ni80Y10Al10 film have changed to nanosized crystalline with the same size of about 12.3nm when crystallization occurred.展开更多
Scanning tunneling microscopy was used to measure the mean lateral dimensions D of grains at the surface of Ni films with thicknesses ranging from 15 to 200nm.The same films were analyzed by x-ray diffraction to obtai...Scanning tunneling microscopy was used to measure the mean lateral dimensions D of grains at the surface of Ni films with thicknesses ranging from 15 to 200nm.The same films were analyzed by x-ray diffraction to obtain the average linear dimensionsδof coherent scattering regions in the direction normal to the film plane(coherence depths).For thin Ni films condensed on single sapphire substrate at room temperature,these two lengths D andδare equal and increase with film thickness.But for films thicker than 130nm,these two lengths have different constant values and D>δ.This is because the coherent scattering depth is not only limited by the grain sizes but also by various defects in the grains.The difference between the constant values of D andδdisappears for films after annealing for 30min at 423K in the ultra-high vacuum system.展开更多
文摘Ternary thin Ni90-xYxAl10 films have been prepared by using cocondensation method under ultrahigh vacuum condition.Films with a wide concentration range between Ni80Y10Al10 and Ni20Y70AI10 were found to be amorphous.With an addition of 10at.%AI the thermal stability of binary amorphous NiY has been enhanced.This is caused by a more closely packed structure and the bondings between AI and Ni,Y may also play an important role.The surface investigation by scanning tunneling microscopy suggests that the atom redistribution and the crystallization have been limited in the clusters with a size of about 10.5nm.The nanosized amorphous clusters of Ni80Y10Al10 film have changed to nanosized crystalline with the same size of about 12.3nm when crystallization occurred.
文摘Scanning tunneling microscopy was used to measure the mean lateral dimensions D of grains at the surface of Ni films with thicknesses ranging from 15 to 200nm.The same films were analyzed by x-ray diffraction to obtain the average linear dimensionsδof coherent scattering regions in the direction normal to the film plane(coherence depths).For thin Ni films condensed on single sapphire substrate at room temperature,these two lengths D andδare equal and increase with film thickness.But for films thicker than 130nm,these two lengths have different constant values and D>δ.This is because the coherent scattering depth is not only limited by the grain sizes but also by various defects in the grains.The difference between the constant values of D andδdisappears for films after annealing for 30min at 423K in the ultra-high vacuum system.
