Electrical and Magnetic Properties of Quasicrystal Approximants RCd6 (R: Rare Earth)

Abstract

We measured the electrical resistivity, magnetic susceptibility, magnetization, and specific heat of the quasicrystal approximants RCd 6 (R: rare earth, Y–Lu) with a body-centered cubic (bcc) crystal structure. Single crystals were grown by the Cd-self flux method and annealing method. We confirmed that the structural order–disorder transition is realized at about 160 K when the lattice constant a is larger than 15.481 A in YCd 6 , namely, for R = Pr, Nd, Sm, Gd, Tb, Dy, and Yb. At lower temperatures, RCd 6 compounds, except non-4 f reference compounds YCd 6 and LuCd 6 , and a divalent compound YbCd 6 , are found to order antiferromagnetically. We clarified that the structural order–disorder transition has a great influence on the magnetic ordering and transport properties. The Neel temperature of RCd 6 (R: Nd, Sm, Tb, and Dy) with the structural order–disorder transition is appreciably higher than the de Gennes scaling normalized by the Neel temperature of GdCd 6 , while the the Neel temperature of RCd 6...