scholarly journals Far-infrared absorption in Sb-doped Ge epilayers near the metal–insulator transition

2002 ◽  
Vol 80 (19) ◽  
pp. 3536-3538 ◽  
Author(s):  
Jordana Bandaru ◽  
Jeffrey W. Beeman ◽  
Eugene E. Haller
Keyword(s):  
Infrared Absorption ◽  
Far Infrared ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator

STUDY OF POSITRON LIFETIME AND INFRARED SPECTROSCOPY FOR Pr-SUBSTITUTED YBa2Cu3O7-δ SYSTEMS

2004 ◽  
Vol 18 (22) ◽  
pp. 3001-3014 ◽  
Author(s):  
GUIXIN CAO ◽  
JINCANG ZHANG ◽  
SHIXUN CAO ◽  
CHAO JING ◽  
XUECHU SHEN
Keyword(s):  
Infrared Spectroscopy ◽  
Infrared Absorption ◽  
Oxygen Vacancies ◽  
Positron Lifetime ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Short Lifetime ◽  
Long Lifetime

The Pr -substituted YBa 2 Cu 3 O 7-δ( Y 123) superconducting systems with the content of 0.0–1.0 have been systematically studied by positron lifetime and infrared absorption experiments. The results show that the short lifetime τ1 decreases as a function of Pr -substitution x below x=0.6, but when above x=0.6, it increases inversely. The long lifetime τ2 decreases as a function of Pr -substituted x. Based on the present results, we discuss that Pr 4+ substitutes on Ba 2+ ion and forms Pr Ba defects. The variation of τ1 is caused by the oxygen vacancies and τ2 is probably affected by the absence of Cu due to Pr Ba defects. The infrared absorption of Pr -substituted Y 123 systems gives three variational modes, located at 560 cm -1( A 1), 1435 cm -1( A 2) and 1631 cm -1( A 3) respectively. Here the A 3 mode shows that with Pr content increasing from x=0.1 to 1.0, the infrared absorption decreases and the peak tends to broaden. So, combining with the results of the positron lifetime spectra, we can argue that there always exists portion of Pr Ba defects in the Pr -substituted systems, and the Pr 4+ substituted into Ba 2+ is also increasing with the Pr content increasing. When the Pr content is 0.6, the systems have a metal-insulator transition and Pr Ba defects begin to domain the samples' microstructure.

Far-infrared studies of the metal-insulator transition in PrNiO3 and NdNiO3

1994 ◽  
Vol 235-240 ◽  
pp. 1289-1290 ◽  
Author(s):  
A. Wittlin ◽  
A.M. Gerrits ◽  
X. Granados ◽  
J.L. Garcia-Muñoz ◽  
J. Fontcuberta
Keyword(s):  
Far Infrared ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Infrared Studies

Metal-insulator transition in (Pr,Y)0.7Ca0.3CoO3 in the far-infrared spectral region

2020 ◽  
Vol 102 (19) ◽  
Author(s):  
H. Němec ◽  
C. Kadlec ◽  
V. Goian ◽  
F. Borodavka ◽  
V. Železný ◽  
...  
Keyword(s):  
Spectral Region ◽  
Far Infrared ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Infrared Spectral Region ◽  
Infrared Spectral
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