Atomic structure of the i-R-Cd quasicrystals and consequences for magnetism

Crystal electric field excitations in the quasicrystal approximantTbCd6studied by inelastic neutron scattering

“…For i-RCd quasicrystals, however, ∼60 -70% of the R ions are associated with the R icosahedron within the Tsai-type cluster, and the balance are contained within the double Friauf polyhedron (DFP) that fill the gaps between the clusters. 19,20 Furthermore, a recent 6-D structural refinement of the i-R-Cd quasicrystals (R = Gd, Dy and Tm) noted a degree of chemical disorder on the nominally R icosahedron itself. 20 Nevertheless, a comprehensive understanding of the nature of magnetism in the RCd 6 approximants provides an important starting point for elucidating the magnetic interactions in the corresponding quasicrystals.…”

“…19,20 Furthermore, a recent 6-D structural refinement of the i-R-Cd quasicrystals (R = Gd, Dy and Tm) noted a degree of chemical disorder on the nominally R icosahedron itself. 20 Nevertheless, a comprehensive understanding of the nature of magnetism in the RCd 6 approximants provides an important starting point for elucidating the magnetic interactions in the corresponding quasicrystals. In particular, for R magnetic ions, investiga- T = 300 K. Data were taken at IN4 spectrometer using an incident neutron wavelength of 3Å (Ei = 9.3 meV).…”

Study of rare earth local moment magnetism and strongly correlated phenomena in various crystal structures

“…As a support argument that they belong to the same structural family, we can compare the measured values for a 6D to the lattice constant, a, expected for the RCd 6 approximant phase through the well-established relation [125]: This is confirmed recently by a full 6D structural refinement of the i-R-Cd quasicrystal as was done for i-Yb-Cd 5.7 [80; 139]. In the case of i-R-Cd, both the rhombic triacontahedral clusters and the Tsai-type atomic cluster were found to show certain degree of Cd/R partial occupancy [139]. The deficiency of R in the Tsai-type cluster may result from a deviation of the atomic size ratio between R and Cd, from the ideal value for Tsai-type cluster, 1.288 [140].…”

“…, where there is a full occupancy of Yb 2+ in the Tsai-type cluster, the atomic size ration between Yb 2+ and Cd is ∼1.237, a value that is very close to the ideal ratio [139].…”

“…For i-R-Cd quasicrystals, I synthesized samples for optical conductivity measurements [250] and also for structural refinement [139]. In addition, isotopic Cd was used to prepare samples for neutron scattering experiments (results will be published later).…”