Applications and limitations of electron correlation microscopy to study relaxation dynamics in supercooled liquids

作者：Zhang Pei; He Li; Besser Matthew F; Liu Ze; Schroers Jan; Kramer Matthew J; Voyles Paul M^*

来源：Ultramicroscopy, 2017, 178: 125-130.

DOI：10.1016/j.ultramic.2016.09.001

• Electron correlation microscopy
• Supercooled liquid
• Structural relaxation time
• Metallic glass
• In-situ heating

Electron correlation microscopy (ECM) is a way to measure structural relaxation times, tau, of liquids with nanometer-scale spatial resolution using coherent electron scattering equivalent of photon correlation spectroscopy. We have applied ECM with a 3.5 nm diameter probe to Pt57.5Cu14.7Ni53P22.5 amorphous nanorods and Pd40Ni40P20 bulk metallic glass (BMG) heated inside the STEM into the supercooled liquid region. These data demonstrate that the ECM technique is limited by the characteristics of the time series, which must be at least 40 tau to obtain a well-converged correlation function g(2)(t), and the time per frame, which must be less than 0.1 tau to obtain sufficient sampling. A high-speed direct electron camera enables fast acquisition and affords reliable g2(t) data even with low signal per frame.

• 出版日期2017-7