Development of 3He insert for Magnetization Measurements down to T = 0.4 K with SQUID magnetometer

International Conference on Strongly Correlated Electron Systems 2014

Sato, Yoshiaki^1 ; Hasuo, Tadahiko^1 ; Inagaki, Yuji^1 ; Kawae, Tatsuya^1

Department of Applied Quantum Physics, Kyushu University, Fukuoka

819-0385, Japan^1

关键词: Magnetization measurements;    Non-Fermi-liquid behavior;    Nonlinear susceptibilities;    Quadrupolar Kondo effect;    Quadrupolar moments;    SQUID magnetometers;    Superconducting quantum interference;    Temperature dependence;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/592/1/012147/pdf
DOI  :  10.1088/1742-6596/592/1/012147

来源: IOP

【 摘 要 】

We have developed a 9-mm-diameter3He insert for precise magnetization measurements down to T =0.4 K that is attachable to a commercial superconducting quantum interference device magnetometer. The insert is made from a thin-walled stainless steel pipe with an inner diameter of 6.2 mm, which determines the maximum sample size.3He gas is condensed in the pipe, which is liquefied by4He gas at T =1.8 K generated by the magnetometer via the heat exchanger of a Cu vacuum jacket with an outer diameter of 8.6mm soldered to the stainless steel pipe. The temperature of the insert is decreased to T 0=.5 K by evacuating liquid3He using a rotary pump and then to T -0.36 K with a sorption pump. From the diamagnetization signal of a superconducting Al chip with a mass below 0.1 mg, the magnetization resolution with the insert is confirmed to be less than 10-7emu. We measure the temperature dependence of magnetization down to T =0.5 K in PrxLa1-xPb3, which is a good candidate for the reality of the quadrupolar Kondo effect, using the3He insert. Non-Fermi liquid behavior of the nonlinear susceptibility in χ3with a -lnT dependence is detected in the [100] and [110] directions below T =2.5 K, suggesting the screening of quadrupolar moments. In contrast, χ3in the [111] direction becomes constant below T =3 K. The observed features indicate that a low-lying Γ3doublet plays a crucial role in the anomalous properties of PrxLa1-xPb3.