Low Temperature Phase Transition (Pt) and Defect Formation (Df) in Silicon with Dioxide Inclusions Under X-Ray Irradiation

1995 ◽  
Vol 396 ◽  
Author(s):  
SH.M. Makhkamov ◽  
S.N. Abdurakhmanova
Keyword(s):  
Phase Transition ◽  
Charge Exchange ◽  
Defect Formation ◽  
Exchange Process ◽  
Temperature Phase ◽  
X Rays ◽  
Charge Exchange Process ◽  
X Ray ◽  
Temperature Phase Transition ◽  
A Charge

AbstractStudies of galvanomagnetic and electrical parameters of p- type Si : SiO2 in the temperature range 80 – 400 K have shown that X-ray irradiation at 80 K (Mo Ka,β and braking radiation hvmax. = 50 heV) leads to various transformations of the spectrum of electron- hole states in the band gap of such material, depending on the flux density of the X-rays. Two main processes are observed: the defect (vacancy and divacancy) formation and a charge exchange of native defects localized at the Si – SiO2 interface. The charge exchange process is rather collective and stimulated one because it is in response to an X-ray-induced ferroelectric phase transition in the SiO2- phase.

scholarly journals High-temperature phase transition of SrRuO3and SrHfO5: X-ray diffraction and PAC spectroscopy

1996 ◽  
Vol 52 (a1) ◽  
pp. C364-C364
Author(s):  
J. A. Guevara ◽  
S. L. Cuffini ◽  
Y. P. Mascarenhas ◽  
P. de la Presa ◽  
A. Ayala ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Temperature ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Pac Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Phase Transition

Possible low-temperature phase transition of Langmuir–Blodgett films of a charge–transfer complex detected by ESR

1998 ◽  
Vol 327-329 ◽  
pp. 391-394
Author(s):  
Keiichi Ikegami ◽  
Shin-ichi Kuroda ◽  
Tomoyuki Akutagawa ◽  
Taro Konuma ◽  
Takayoshi Nakamura ◽  
...  
Keyword(s):  
Phase Transition ◽  
Charge Transfer ◽  
Low Temperature ◽  
Charge Transfer Complex ◽  
Temperature Phase ◽  
Langmuir Blodgett ◽  
Langmuir Blodgett Films ◽  
Temperature Phase Transition ◽  
A Charge ◽  
Low Temperature Phase

scholarly journals Negative X-Ray Expansion in Cadmium Cyanide

2020 ◽  
Author(s):  
Chloe Coates ◽  
Claire A. Murray ◽  
Hanna Boström ◽  
Emily Reynolds ◽  
Andrew Goodwin
Keyword(s):  
Mechanical Response ◽  
Local Heating ◽  
Negative Thermal Expansion ◽  
Functional Materials ◽  
Temperature Phase ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cadmium Cyanide ◽  
Temperature Phase Transition

Cadmium cyanide, Cd(CN)<sub>2</sub>, is a flexible coordination polymer best studied for its strong and isotropic negative thermal expansion (NTE) effect. Here we show that this NTE is actually X-ray exposure dependent: Cd(CN)<sub>2</sub> contracts not only on heating but also on irradiation by X-rays. This behaviour contrasts that observed in other beam-sensitive materials, for which X-ray exposure drives lattice expansion. We call this effect ‘negative X-ray expansion’ (NXE) and suggest its origin involves an interaction between X-rays and cyanide ‘flips’; in particular, we rule out local heating as a possible mechanism. Irradiation also affects the nature of a low-temperature phase transition. Our analysis resolves discrepancies in NTE coefficients reported previously on the basis of X-ray diffraction measurements, and we establish the ‘true’ NTE behaviour of Cd(CN)<sub>2</sub> across the temperature range 150–750 K. The interplay between irradiation and mechanical response in Cd(CN)<sub>2</sub> highlights the potential for exploiting X-ray exposure in the design of functional materials.

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