**Acknowledgements**

We are grateful to R. Rüffer (Grenoble) and S. Stankov (Karlsruhe) for stimulating discussions. Samples of metallic glasses were provided by a courtesy of D. Janičkovič (Bratislava). The authors would like to thank P. Švec (Bratislava), J. Kohout (Prague), and A. Lančok (Husinec-Řež) for their technical assistance during measurements on the synchrotron and V. Vrba (Olomouc) for his help with data processing. Financial support of the grants GAČR 14-12449S, IGA\_PrF\_2016\_022, and VEGA 1/0182/16 is acknowledged.
