Crystal structure and low-temperature magnetic properties of R2Au2Pb (R = Y, La–Nd, Sm, Gd–Lu) plumbides

Анотація

Polycrystalline samples of the ternary compounds R₂Au₂Pb (R = Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) were studied by means of powder X-ray diffraction and magnetic measurements. All these materials were found to crystallize with a tetragonal crystal structure of the Er₂Au₂Sn type (space group P4₂/mnm, Pearson code tP20). The Y-, La-, and Lu-based phases were established to be diamagnetic, while Yb₂Au₂Pb was characterized as an intermediate valence system due to an unstable 4f shell. All the other R₂Au₂Pb ternaries were found to order antiferromagnetically at low temperatures (T_N in the range 2–30 K) due to the localized magnetic moments carried on trivalent R³⁺ ions.