9 research outputs found
EXAFS studies of intermediate crystallisation steps of amorphous Ni-Zr alloys
Metallic Ni-Zr glasses show characteristic exothermic processes during crystallisation as observed with differential scanning calorimetry (DSC). In the glassy alloy NiZr, after the first of the two exothermic reactions leading to complete crystallisation an intermediate amorphous stage is found. The X-ray absorption near-edge structure (XANES) and the extended X-ray absorption fine structure (EXAFS) of such an alloy are compared to those for the as-cast alloy and to those for an intermediate crystallisation step, an alloy with the nominal composition NiZr
Structural Investigation of Bond-Isomeric Hexakis (Thiocyanato-isothiocyanato) osmates from Os -Edge
Critical cluster size for mixed valence in small matrix-isolated Sm clusters
From L3 absorption measurement, information on the valence and size of small matrix-isolated Sm clusters is obtained by analyzing the x-ray-absorption near-edge structure and the extended x-ray-absorption fine structure (EXAFS). Depending on the mean cluster size, which is a function of the atomic concentration (Sm to rare-gas atom ratio), every valence between 2.0 and 3.0 is reproducibly achievable. At very low Sm concentrations the samples have the atomic valence; at a critical concentration c≊1:100 a steep rise of the valence up to v=2.6 is found. Then, with increasing metal concentration, the Sm-cluster valence approaches the valence of the solid. From EXAFS analysis, a mean cluster size of 13 atoms for clusters with v=2.6 follows. The mixed valence of the Sm atoms is explained by the pressure exerted on the Sm cluster by the distorted rare-gas lattice (the rare gas is Ne, Ar, or Kr)
EXAFS: Possibilities, advantages and limitations for the investigation of local order in metallic glasses
SIGLEDEGerman
Valence fluctuations of Sm in an Ar-matrix
SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman