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Phys. Rev. Lett. 103, 115502 (2009) [4 pages]

Initial Structure Memory of Pressure-Induced Changes in the Phase-Change Memory Alloy Ge2Sb2Te5

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M. Krbal1,2, A. V. Kolobov2, J. Haines1, P. Fons2, C. Levelut3, R. Le Parc3, M. Hanfland4, J. Tominaga2, A. Pradel1, and M. Ribes1
1Institut Charles Gerhardt, UMR 5253 CNRS-UM2-ENSCM-UM1, PMDP/PMOF, Université Montpellier II, Place Eugène Bataillon, Montpellier Cedex 5, France
2Center for Applied Near-Field Optics Research (CanFor), National Institute of Advanced Industrial Science and Technology, 1-1-1, Higashi, Tsukuba 305-8562, Japan
3Laboratoire des Colloides, Verres et Nanomatériaux, Université Montpellier II, Place Eugène Bataillon, Montlpellier Cedex 5, France
4European Synchrotron Radiation Facility (ESRF), 6 rue Jules Horowitz, Boîte Postale 220, F38043, Grenoble, France

Received 21 April 2009; published 9 September 2009

We demonstrate that while the metastable face-centered cubic (fcc) phase of Ge2Sb2Te5 becomes amorphous under hydrostatic compression at about 15 GPa, the stable trigonal phase remains crystalline. Upon higher compression, a body-centered cubic phase is obtained in both cases around 30 GPa. Upon decompression, the amorphous phase is retained for the starting fcc phase while the initial structure is recovered for the starting trigonal phase. We argue that the presence of vacancies and associated subsequent large atomic displacements lead to nanoscale phase separation and loss of initial structure memory in the fcc staring phase of Ge2Sb2Te5.

© 2009 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.103.115502
DOI:
10.1103/PhysRevLett.103.115502
PACS:
61.50.Ks, 61.05.cp, 62.50.−p, 81.30.Hd