Studies of dissipative state in non-Kramers system Pr-based compounds

超声波测量表明，PrMg 3的弹性常数（C11-C12）/2随磁场的变化表现出很强的磁各向异性。我们得到了小Gruneisen常数为5 PrMg 3在低温下从低温热膨胀测量。这一结果意味着PrMg 3具有小态密度的类粒子。我们还进行了比热和磁化强度测量PrV 2Al 20。我们的测量结果表明，PrV_2Al_（20）在零场下表现出TQ = 0.73 K和T* = 0.61 K的两相转变。我们描述了在三个主要方向的T-H相图。应该强调的是，高场相位仅存在于[100]场方向。我们提出高场相是由于八极矩辅助下的电四极O20相到O22相的转换。

Ultrasonic measurements on PrMg3 reveals that the magnetic field dependence of elastic constant (C11-C12)/2 shows strong magnetic anisotropy. We obtained small Gruneisen constant of 5 for PrMg3 at low temperatures from low-temperature thermal expansion measurements. This result implies that PrMg3 has sermonic quasiparticles with small density of states. We have also performed specific heat and magnetization measurements on PrV2Al20. Our measurements reveals that PrV2Al20 exhibits two-phase transition at TQ = 0.73 K and T* = 0.61 K at zero field. We describe a T-H phase diagram in the three principal directions. It should be emphasized that high field phase exists in only [100] field direction. We proposed that the high field phase is due to the switching from the electric quadrupole O20 phase to O22 phase assisted by the octupole moment.