Short range order and stability of amorphous GexTe 100-x alloys (12 ≤ x ≤ 44.6)

P. Jóvári, A. Piarristeguy, R. Escalier, I. Kaban, J. Bednarčik, A. Pradel

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Amorphous GexTe100-x alloys were obtained over a broad composition range (12 ≤ x ≤ 44.6) by thermal co-evaporation. Their structure was investigated by x-ray diffraction and extended x-ray absorption fine structure measurements. Experimental datasets were fitted simultaneously by the reverse Monte Carlo simulation technique. It is concluded that Te is mostly twofold coordinated and the majority of Ge atoms have four neighbours. The number of Ge-Ge and Te-Te bonds evolves monotonically with composition. Ge-Ge bonding can be observed already at x = 24 while Te-Te bonds can be found even in Ge44.6Te55.4. The models obtained by simulation show that the structure of compositions with x > 24 should be considered as a random covalent network but there is chemical ordering for x ≤ 24, exactly in the composition range where glasses can be obtained from the melt by fast quenching. The composition dependences of some physical properties also point to the connection between chemical short range order and the stability of the amorphous phase: while the glass transition temperature and microhardness increase monotonically with the composition, the thermal stability of the amorphous films goes through a maximum around x = 20-24.

Original languageEnglish
Article number195401
JournalJournal of Physics Condensed Matter
Volume25
Issue number19
DOIs
Publication statusPublished - May 15 2013

Fingerprint

Glass
Hot Temperature
X-Rays
Transition Temperature
Chemical analysis
X rays
Amorphous films
x ray absorption
Microhardness
microhardness
glass transition temperature
Quenching
Evaporation
x ray diffraction
Thermodynamic stability
thermal stability
simulation
Physical properties
Diffraction
physical properties

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Materials Science(all)
  • Medicine(all)

Cite this

Short range order and stability of amorphous GexTe 100-x alloys (12 ≤ x ≤ 44.6). / Jóvári, P.; Piarristeguy, A.; Escalier, R.; Kaban, I.; Bednarčik, J.; Pradel, A.

In: Journal of Physics Condensed Matter, Vol. 25, No. 19, 195401, 15.05.2013.

Research output: Contribution to journalArticle

Jóvári, P. ; Piarristeguy, A. ; Escalier, R. ; Kaban, I. ; Bednarčik, J. ; Pradel, A. / Short range order and stability of amorphous GexTe 100-x alloys (12 ≤ x ≤ 44.6). In: Journal of Physics Condensed Matter. 2013 ; Vol. 25, No. 19.
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