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利用等离子体增强化学气相沉积技术制备了厚度不同的Ge薄膜,随着样品厚度的减小,样品表现出了室温铁磁性.厚度为12nm样品经过300C退火后,由于颗粒细化,颗粒之间的界面增加,界面缺陷增加,样品表现出最大的铁磁性(50emu/cm3).场冷却和零场冷却曲线测试表明居里温度约为350K.进行600C退火后,颗粒团聚,样品的铁磁性最小.当样品厚度进一步减小为6nm时,沉积态样品表现出铁磁性和顺磁性共存.对6nm厚的样品进行300C退火后,样品只具有铁磁性.进行600C退火后,样品却只具有顺磁性.12nm和6nm厚的Ge纳米结构薄膜随退火温度变化表现出不同的磁性规律,我们认为是由于样品的颗粒大小和颗粒分布不同造成的.样品越薄,Si基底与Ge薄膜之间的界面缺陷越明显,界面缺陷以及Ge颗粒之间的界面缺陷为样品提供了未配对电子,未配对电子的铁磁性耦合强度与样品颗粒的分布以及颗粒之间的结合有一定的关系.颗粒之间分散或颗粒之间的融合程度大都将会降低样品的铁磁性.
Ge films with different thicknesses were prepared by plasma-enhanced chemical vapor deposition, and the samples showed room-temperature ferromagnetism as the sample thickness decreased.After annealing at 300 C for a sample with a thickness of 12 nm, due to the grain refinement, The interface increases and interface defects increase, and the sample exhibits the maximum ferromagnetic (50 emu / cm3). Field cooling and zero field cooling curve tests show that the Curie temperature is about 350 K. After 600 C annealing, the particles agglomerate and the sample has the smallest ferromagnetism. When the thickness of the sample was further reduced to 6 nm, the as-deposited samples showed coexistence of ferromagnetism and paramagnetic.The samples were ferromagnetic only after 300 C annealing of 6 nm thick samples.The samples were only paramagnetic after annealing at 600 C. 12 nm And 6nm thick Ge nanostructured films show different magnetic laws with the annealing temperature, which is considered to be due to the different particle size and particle distribution of the sample.The thinner the sample, the more obvious the interface defects between the Si substrate and the Ge film , Interfacial defects and interfacial defects between the Ge particles provide unpaired electrons for the sample, the ferromagnetic coupling strength of the unpaired electrons and the distribution of the sample particles and the particle Binding between a certain relationship between the degree of integration or particles dispersed between the particles will reduce most of the ferromagnetic sample.