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

对PrMg3的超声测量表明，弹性常数(C11-C12)/2对磁场的依赖表现出较强的磁各向异性。通过低温热膨胀测量，我们得到PrMg3在低温时的Gruneisen常数很小，为5。这一结果表明，PrMg3具有小态密度的半粒子。我们还对PrV2Al20进行了比热和磁化测量。我们的测量结果表明，PrV2Al20在TQ = 0.73 K和T* = 0.61 K时表现出两相转变。我们描述了三个主要方向上的T-H相图。需要强调的是，高场相位只存在于[100]场方向。我们提出高场相位是由于电四极O20相在八极矩的帮助下切换到O22相。

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.