Local structural changes in a Gd₆₅Cu₃₅metallic glass by cryogenic rejuvenation: comparison with other Gd transition...

As a part of a systematic study on the structural changes of Gd-transition metal (TM) alloy glasses induced by cryogenic rejuvenation, high-energy x-ray diffraction (HEXRD) and anomalous x-ray scattering (AXS) measurements were performed on a GdCumetallic glass (MG) possessing minimal elastic heterogeneity, as indicated by dynamical mechanical analysis. Significant structural changes were observed in this MG as a result of temperature cyclings between liquid Nand room temperatures 40 times. (1) HEXRD revealed minor changes in the first nearest neighbour range of the pair distribution function,, consistent with observations in other GdTMglasses. (2) The partial structural information obtained from HEXRD and AXS showed that Gd-Cu and Cu-Cu partial correlations dominate the first peak region of the total, whereas Gd-Gd correlations contribute mainly to the second peak. (3) Additionally, some of the Gd-Cu and Cu-Cu correlations extend to the second peak of the total, unlike in GdCoand GdNiMGs. (4) Futhermore, Cu atoms shift farther from each other by cryogenic rejuvenation. (5) Heterogeneities in the Cu elemental composition and the total number density at nm length scale increase by cryogenic rejuvenation, similar to the GdCoMG but opposite to the trend observed in the GdNiMG. Accordingly, these findings suggest that structural heterogeneity in MGs is not systematically related to the extent of elastic heterogeneity.