排序方式: 共有117条查询结果,搜索用时 562 毫秒
71.
提出了利用霍耳效应测量研究非晶态材料结构弛豫的方法。第一次实验研究了金属型非晶态InSb的结构弛豫,结果表明,霍耳效应测量是研究非晶材料结构弛豫的有效方法,并能直接判断出发生结构弛豫的物理机制。 相似文献
72.
利用欧姆加热三元共蒸的方法制备了 Y-Ba-Cu-O 薄膜.研究了组分、热处理温度和降温速度诱导的金属-半导体转变及其对超导电性的影响.在这些研究的基础上,第一次利用欧姆加热三元共蒸方法获得了零电阻温度超过液氮温度的 Y-Ba-Cu-O 超导薄膜.其起始超导 T_c为98K,零电阻超导 T_c 为78.6K,中点超导 T_c 为84K,△T_c 为12K. 相似文献
73.
在Y_1Ba_2Cu_3O_(7 8)单相大块样品中第一次观察到零电阻为103.2K的超导现象,但它是不稳定的,其T_c值逐渐降低。研究了样品的磁化和J_c(B)性质。认为Cu-O链的不完全的和不稳定的Peirls相变导致了100K以上超导现象的出现。 相似文献
74.
采用直流磁控溅射法在NdGaO3 ( 110 )衬底上制备了La2/3Ca1/3MnO3-δ外延单晶薄膜 .在 0~8T的磁场范围内测量了不同温区下的磁电阻随磁场的变化关系 .结果表明 ,ρ(H )遵循以下规律 :当温度高于居里温度TC 时 ,ρ(H ) =1α(T) + β(T)H2 ;当T <Tc时,ρ(H ) =ρ0(T ) +1A(T)+B(T)exp(H/C(T));而当温度远低于居里温度时,ρ(H ) =1σ(T) + ν(T)H。表明负巨磁电阻的产生主要起因于磁场引起的电导率的增加。 相似文献
75.
SUPERCONDUCTING TRANSITION TEMPERATURES AND NORMAL-STATE ELECTRICAL RESISTIVITIES OF Tm1-xPrxBa2Cu3O7-δ 下载免费PDF全文
曹效文 《物理学报(海外版)》1994,3(8):583-588
Superconducting transition temperature Tc and normal-state electrical resistivities ρ of the Tm1-xPrxBa2Cu3O7-δ system have been measured. The results indicate that Tc remains constant for x = 0 to 0.08 before it drops steadily with higher x. Following the Abrikosov-Gor'kov model, a total suppression of superconductivity occurs at a critical Pr concentration xcr≈0.56. It is found for the first time, as far as we know, that the logarithmic resistivity at 270 K increases linearly with increasing x, yielding ρ= ρ0eax. Judging from the relation between dρ/dT and x, a metal to insulator transition occurs just beyond xcr. 相似文献
76.
测量了有机超导体κ(BEDTTTF)2Cu(SCN)2单晶的X射线衍射和强磁场下磁阻.样品沿垂直于传导面的晶格常数为1.49nm.在1.2K温度,磁场垂直于传导面的位形下,在6T以上观测到磁阻振荡,即ShubnikovdeHas效应.由FFT(FastFouierTransformation)谱图,我们发现了对应于κ(BEDTTTF)2Cu(SCN)2单晶Fermi面闭合轨道Fα频率和开放轨道磁突破频率Fβ的存在,Fα=620±30T,Fβ=4100±200T. 相似文献
77.
78.
利用透射电子显微镜(TEM)对有化合物生成(Pd2Ge和PdGe等)的Pd,Ge薄膜体系中的分形晶化行为进行了系统研究实验结果和分析表明:在各种退火温度条件下,Pd-Ge共蒸膜都难以发生分形晶化,Pd/a-Ge双层膜较a-Ge/Pd双层膜更容易导致分形结构的产生Z化合物Pd2Ge和PdGe的形成对薄膜中的分形晶化有明显的抑制作用,体系中能否出现分形结构,取决于非晶Ge的成核生长和Pd,Ge化学反应两种过程的相互竟争.
关键词: 相似文献
79.
PHOTOELECTRON SPECTROSCOPIC STUDY OF THE EFFECT OF Cs INTRALAYER ON THE BAND LINEUP OF Ge/InP(100) HETEROJUNCTION 下载免费PDF全文
The formation and band lineup of the Ge/InP(100) interface with or without alkali metal Cs intralayer (IL) are studied by means of X-ray photoemission spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS). It is found that the Cs atoms do not react with or diffuse into the subatrate and the Ge overlayer. The thin Cs IL will induce an increase of the valence band offset (ΔEv) for the Ge/InP(100) heterojunction. The changes of ΔEv are proportional to the IL thickness and them saturate for IL thickness of about one half of a monolayer of Cs IL. Without the IL, ΔEv of the Ge/InP(100) heterojunction is equal to 0.70eV, and ΔEv with one half of monolayer IL is up to 0.90eV. These results show that the interface dipole plays a major role in the band lineup at the heterojunction interface. 相似文献
80.
SUPERCONDUCTING TRANSITION TEMPERATURES AND NORMAL-STATE ELECTRICAL RESISTIVITIES OF Tm1-xPrxBa2Cu3O7-δ 下载免费PDF全文
Superconducting transition temperature Tc and normal-state electrical resistivities ρ of the Tm1-xPrxBa2Cu3O7-δ system have been measured. The results indicate that Tc remains constant for x = 0 to 0.08 before it drops steadily with higher x. Following the Abrikosov-Gor'kov model, a total suppression of superconductivity occurs at a critical Pr concentration xcr≈0.56. It is found for the first time, as far as we know, that the logarithmic resistivity at 270 K increases linearly with increasing x, yielding ρ= ρ0eax. Judging from the relation between dρ/dT and x, a metal to insulator transition occurs just beyond xcr. 相似文献