Living metals

European researchers have shown that the microscopic structure of a crystalline material fluctuates in time.

Using synchrotron x-ray microbeams, a research team from the Max Planck Institute for Metals Research in Stuttgart and the European Synchrotron Radiation Facility (ESRF) has shown that the microscopic structure of a crystalline material fluctuates in time.

The structure of crystalline materials change when they are heated, and scientists can observe this by means of a diffraction experiment using X-rays: one class of interference peaks associated with the low-temperature structure disappears, while another class of X-ray peaks belonging to the new structure emerges.

For a fixed temperature, however, the x-ray diffraction pattern has hitherto always been believed to be static. Now, however, the researchers have shown that this x-ray diffraction pattern shows fluctuations in time.

In their experiments, the research team investigated a metal alloy, composed of iron and aluminium. They used the ID22 beamline at the ESRF to focus a beam of 2×2 µm2 on a small 2x2x2 µm3 sample volume of the material.

They noticed that the intensity of the diffracted x-ray beam from the alloy fluctuated in time – proving for the first time that temporal structural fluctuations on an atomic scale are present in such crystalline material.