Ultrasonic Study on the Hexagonal Antiferromagnet Dy₃Ru₄Al₁₂

The Crystal Electric Field Effect in the Distorted Kagome Lattice Ferromagnet Nd3Ru4Al12

“…It was reported that the origin of reduced magnetic moments is likely owing to the CEF effect and competing exchange and anisotropy interactions, however, the CEF effect is unclear at present [4]. On the other hand, we previously measured the elastic moduli by using ultrasonic technique and reported that there is no characteristic softening arising from the CEF effect in Nd [12][13][14]17]. This indicates that a coupling constant of a quadrupole interaction between strains and corresponding quadrupoles is relatively small in this compound.…”

“…The R ions form a distorted kagome net in c-planes. The compounds R 3 Ru 4 Al 12 have been intriguingly studied from the viewpoint of the effect of geometrical frustration, for instance, an antiferromagnetic transition and a field-induced quadrupolar ordering in Dy 3 Ru 4 Al 12 , a helical ordering of spin trimers in Gd 3 Ru 4 Al 12 , and so on [4][5][6][7][8][9][10][11][12][13][14][15][16].…”

Quadrupolar Response from the Crystal Electric Field Level Scheme Consisting of Only Kramers Doublets in DyNiAl

“…The softenig is caused by an interlevel quadrupole interaciton between the ground doublet and the excited doublets, such as our previous Table I. Fitting parameters of C 44 :  (K), T C - (K), a (GPa), b (10 -5 GPa/K 2 ), and c (10 -10 GPa/K 4 [3][4][5][6]. We obtained information of the quadrupole interaction in the 4f-electronic states of the Dy 3+ ion under the hexagonal CEF from the temperature dependence of C 44 .…”

“…They show interesting physical properties, such as multipolar ordering [1,2]. Recently, we reported multipolar (quadrupolar) ordering in Dy-based compounds, DyNi 3 Ga 9 and Dy 3 Ru 4 Al 12 (magnetic-field-induced phase) [3][4][5][6]. Although 16-fold multiplet of the total angular moment in the free Dy 3+ ion splits into eight Kramers doublets with no quadrupole degeneracy under the trigonal (and hexagonal) crystal electric field (CEF), these compounds exhibit quadrupolar ordering originating from an interlevel quadrupole interaction between the ground and excited states.…”

Ultrasonic Dispersion in the Hexagonal Ferromagnet Nd3Ru4Al12

“…The ternary compounds R 3 Ru 4 Al 12 (R: rare earth element) crystallize in the hexagonal Gd 3 Ru 4 Al 12 -type structure (space group P6 3 /mmc) [6][7][8][9][10][11][12][13][14][15][16][17][18]. This crystal has no cage structure.…”