Akatsu Mitsuhiro, Goto Terutaka, Suzuki Osamu, Nemoto Yuichi, Nakamura Shintaro, Kunii Satoru, Kido Giyuu
Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan.
Phys Rev Lett. 2004 Oct 8;93(15):156409. doi: 10.1103/PhysRevLett.93.156409.
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. The hybrid magnet (Gama) in the National Institute for Materials Science was employed for high-field measurements up to 30 T and a 3He-4He dilution refrigerator was used for low-temperature experiments down to 20 mK. The phase boundary from paramagnetic phase I to AFQ phase II under [001] magnetic fields closes at H(I-II) approximately 29 T, while the boundary is still open under fields along the [110] and [111] directions even up to 30 T. This anisotropic character of phase II in fields is consistent with the theoretical calculation based on the O(xy)-type AFQ ordering. We also found that AFM phase III reduces considerably in fields turning from the [001] to [110] and [111] directions.
通过超声测量研究了具有Γ(8)基态的Ce0.50La0.50B6中反铁四极子（AFQ）相II和反铁磁（AFM）相III的磁相图。使用了国立材料科学研究所的混合磁体（伽马）进行高达30 T的高场测量，并使用3He-4He稀释制冷机进行低至20 mK的低温实验。在[001]磁场下，顺磁相I到AFQ相II的相界在H(I-II)约29 T处闭合，而在沿[110]和[111]方向的磁场下，即使高达30 T，该边界仍然开放。场中相II的这种各向异性特征与基于O(xy)型AFQ有序化的理论计算一致。我们还发现，AFM相III在从[001]方向转向[110]和[111]方向的磁场中显著减小。
