Quadrupole effects in tetragonal crystals PrCu₂Si₂ and DyCu₂Si₂.

We have investigated quadrupole effects in tetragonal crystals of PrCu2Si2 and DyCu2Si2 by means of low-temperature ultrasonic measurements. The elastic constant C44 of PrCu2Si2 exhibits pronounced softening below 70 K down to a Néel temperature TN = 20 K, which is described in terms of a quadrupole susceptibility for a Γ5 doublet ground state and a Γ3 singlet first excited state located at 15.6 K in the crystalline electric field scheme.

A heterometal single-molecule magnet of [MnIII2NiII2Cl2(salpa)2].

The tetranuclear complex [MnIII2NiII2Cl2(salpa)2] (salpa = N-(2-hydroxybenzyl)-3-amino-1-propanol) has a spin ground state of S = 6 and was confirmed to be an SMM based on a steplike feature of the magnetization hysteresis loop at 0.55 K.

Magnetic anisotropy of the antiferroquadrupole phase in Ce0.50La0.50B6.

Magnetic phase diagrams for antiferroquadrupole (AFQ) phase II and antiferromagnetic (AFM) phase III in Ce0.50La0.50B6 with a Gamma(8) ground state have been investigated by ultrasonic measurements.