scholarly journals Surface X-ray Diffraction Study of the Metal-Insulator Transition on the Si(553)-Au Surface

2008 ◽  
Vol 6 ◽  
pp. 281-285 ◽  
Author(s):  
Wolfgang Voegeli ◽  
Toru Takayama ◽  
Kimitaka Kubo ◽  
Makoto Abe ◽  
Yusaku Iwasawa ◽  
...  
Keyword(s):  
Diffraction Study ◽  
Insulator Transition ◽  
X Ray Diffraction ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
X Ray

EFFECT OF AL ON ELECTRIC CONDUCTIVITY AND SUPERCONDUCTIVITY OF NB-Si-AL-O CERAMIC

1993 ◽  
Vol 07 (25) ◽  
pp. 4261-4270
Author(s):  
S. KOBA ◽  
S. HIGO ◽  
Y. HAKURAKU ◽  
I. KAWANO ◽  
T. OGUSHI ◽  
...  
Keyword(s):  
Electric Conductivity ◽  
Insulator Transition ◽  
X Ray Diffraction ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
X Ray ◽  
Diffraction Patterns

Metal-insulator transition and superconductivity with changing Al composition were observed in the Nb-Si-Al-O system. Semiconductor-like characteristic and normal conductive characteristic were observed for Al <40% and Al >50% respectively. Super-conductive compositions are distributed around the boundary between those two types of conductivity, such as Nb x SiAl (α–x) O z((α, x)=(1.5, 0.7), (2.0,0.8), (3.0, 0.7~1.4)). The superconductivity was confirmed by resistive transitions and diamagnetic transitions. The superconductors in this study have T c =10.0~11.5 K with resistive transitions, and the amplitudes of the diamagnetism reach 30~58% of that of pure Nb powder. X-ray diffraction patterns of any other superconducting Nb-systems such as Nb , Nb 3 Al , Nb 3 Si , NbN , and NbC , have not been observed in Nb-Si-Al-O .

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