Nuclear quadrupole interaction in glassyHf1−xCu<

Abstract

The electric field gradient (EPPES) at Hf sites in amorphous Hf& Cu"alloys was measured for x =0. 33, 0.44, 0.50, and 0.59 with use of the time-differentia1 perturbed angular correlation technique. The results show no evidence of crystallinelike local order in these alloys, supporting a description of their local structure in terms of a dense random packing of atoms. The local and lattice contributions to the EFCx, as well as their dependence on composition, are discussed.

Crystallization steps in Zr- and Hf-based bulk metallic glasses

“…One distribution centered at zero frequency which is associated with nuclei of crystalline Zr 2 Cu, characterized by a low EFG [7], in agreement with other reported results at first stage of crystallization in Zr-Al-Ni-Cu alloys [10,11]. The second EFG component (above 4 × 10 17 V/cm 2 ) can be assigned to the structural site of low EFG component in Zr 6 NiAl 2 .…”

“…In the case of ZTI one of these distributions is characteristic of an amorphous phase [6]. For H65, one EFG distribution has a very low value, close to zero, which is assigned to tetragonal Hf 2 Cu [7] similar to the one observed for Z65, since both compounds are isomorphous. The Z55 sample displays an EFG distribution which has a central value similar to the one of ZTI but not described by a DRP model.…”

“…2b) and Hf 2 (Zr 2 )Ni (open start in Fig. 2b) characterized by a unique EFG [7,8]; Hf 6 (Zr 6 )NiAl 2 (semi full circles in Fig. 2) which have two inequivalent structural sites [9] and a metastable Ti 2 Niphase (full starts in Fig.…”

Thermal evolution of short-range order in Cu–Hf-based amorphous alloys

“…However they are not clearly defined since they have a broad distribution of frequencies (δ ≈ 30%). These components are related to the crystallographic Hf sites in the intermetallic phase Cu 10 Hf 7 (orthorhombic Ni 10 Zr 7 structure) [6][7][8][9][10][11][12].…”

Time-differential perturbed angular correlation study of the electric field gradient in Ti2Rh MoSi2-type compound

“…The smallest V zz values were measured at 4(e) Hf-site in Hf 2 Cu [15] and at the Zr site in Zr 2 Cu [16] compound. This low strength of quadrupole interaction was explained as due to the unusually small value (being of the same order as the d term) of the usually dominant p orbital contribution in this structure [17].…”