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MM: Fachverband Metall- und Materialphysik

MM 65: Liquid & Amorphous Metals II

MM 65.4: Vortrag

Donnerstag, 14. März 2013, 18:00–18:15, H26

Ultrastable Metallic Glass — •Hai-Bin Yu, Yuansu Luo, and Konrad Samwer — I. Physikalisches Institut, Universität Göttingen, Germany

Recently, some novel organic glassy materials, termed *ultrastable glasses* that exhibit remarkable thermodynamic and kinetic stabilities have been prepared by deposition techniques. These ultrastable glasses are at the low energy state on the potential energy landscape, unreachable by quenched glasses that aged for long-time. These materials are of special interest for understanding many fundamental issues regarding the nature of glasses. In this work, we prepared a series of free-standing Zr65Cu27.5Al7.5 metallic glass foils by magnetron sputtering with a very low deposition rate at different substrate temperatures. The resultant materials are homogenously amorphous and have a remarkable higher glass transition temperature Tg than a quenched glass made of the same composition. They are a kind of ultrastable metallic glass. An interesting finding is the ultrastable metallic glass can be prepared only within a narrow substrate-temperature range, from 0.7 to 0.8 Tg of the quenched glass. Above this temperature range the Tg of the deposited glass even decreases. This suggests a signature of surface enhanced relaxation dynamics, a topic currently actively discussed in glassy physics. Structural analysis shows the ultrastable metallic glasses have unique fractural-like nanostructures. H.B. Yu thanks the Alexander von Humboldt Foundation. We acknowledge support from the DFG via the SFB 602 and the Leibniz Program.