During her studies, Arune Makareviciute investigated phase-change materials for novel memory devices, which store data by rapid, reversible switching between amorphous and crystalline states. The work focused on the chalcogenide GeTe and tested whether crystallization speed can be manipulated by thermal treatment (annealing). Using fast calorimetry for thermal analysis together with advanced synchrotron X-ray methods for structural analysis, the study linked the slowdown of GeTe crystallization after annealing to changes in the atomic arrangement of the amorphous phase. The evolution of the crystalline phase during heating was tracked in parallel. To broaden the perspective, the project also established a time–temperature–transformation (TTT) diagram for the related compound Ge15Te85, offering practical insights and highlighting experimental limitations when constructing such diagrams for this class of glasses.

The PhD study was completed at Department of Chemistry, Faculty of Natural Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Friday, 16 January 2025 at 14:30
Place: Building 1511, room 312, Aarhus University, Langelandsgade 140 , 8000 Aarhus C
Title of PhD thesis: Control of crystallization kinetics in Germanium Telluride via thermal annealing and role of β-relaxations
Contact information: Arune Makareviciute, e-mail: arunema@chem.au.dk, tel.: +45 52658601.
Members of the assessment committee:
Professor Isabella Gallino, Chair of Metallic Materials, Technische Universität Berlin, Germany
Professor Morten Mattrup Smedskjær, Department of Chemistry and Bioscience, Aalborg University, Denmark
Associate Professor Tobias Weidner, Department of Chemistry, Aarhus University (chair)
Main supervisor:
Associate Professor Shuai Wei, Department of Chemistry, Aarhus University, Denmark
Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Natural Sciences/GSNS, Ny Munkegade 120, building 1521, 8000 Aarhus C