Magnetic transition and spin fluctuations in the unconventional antiferromagnetic compound Yb3Pt4

Muon spin rotation and relaxation measurements have been carried out on the unconventional antiferromagnet Yb3Pt4. Oscillations are observed below TN = 2.22(1) K, consistent with the antiferromagnetic (AFM) Néel temperature observed in bulk experiments. In agreement with neutron diffraction experiments the oscillation frequency ωμ(T)/2π follows an S = 1/2 mean-field temperature dependence, yielding a quasistatic local field of 1.71(2) kOe at T = 0. A crude estimate gives an ordered moment of ∼ 0.66 μB at T = 0, comparable to 0.81 μB from neutron diffraction. As from above the dynamic relaxation rate λd exhibits no critical slowing down, consistent with a mean-field transition. In the AFM phase a T-linear fit to λd(T), appropriate to a Fermi liquid, yields highly enhanced values of λd/T and the Korringa constant Kμ2T/λd, with Kμ the estimated muon Knight shift. A strong suppression of λd by applied field is observed in the AFM phase. These properties are consistent with the observed large Sommerfeld–Wilson and Kadowaki–Woods ratios in Yb3Pt4 (although the data do not discriminate between Fermi-liquid and non-Fermi-liquid states), and suggest strong enhancement of q≈0 spin correlations between large-Fermi-volume band quasiparticles in the AFM phase of Yb3Pt4.

对非常规反铁磁体Yb₃Pt₄进行了μ子自旋旋转和弛豫测量。在TN = 2.22(1) K以下观察到振荡，这与体实验中观察到的反铁磁（AFM）奈尔温度一致。与中子衍射实验一致，振荡频率ωμ(T)/2π遵循S = 1/2的平均场温度依赖关系，在T = 0时产生1.71(2) kOe的准静态局域场。粗略估计在T = 0时有序磁矩约为0.66 μB，与中子衍射得到的0.81 μB相当。从高温一侧来看，动态弛豫率λd没有临界慢化，这与平均场转变一致。在反铁磁相，对λd(T)进行适合费米液体的T线性拟合，得到λd/T和科林加常数Kμ²T/λd的值大幅提高，其中Kμ是估计的μ子奈特位移。在反铁磁相中观察到施加磁场对λd有强烈抑制作用。这些性质与在Yb₃Pt₄中观察到的大索末菲 - 威尔逊比和卡多瓦基 - 伍兹比一致（尽管数据无法区分费米液体态和非费米液体态），并表明在Yb₃Pt₄的反铁磁相中，大费米体积能带准粒子之间的q≈0自旋关联有强烈增强。