Thermal expansion and magnetostriction measurements using a high sensitive capacitive dilatometer at millikelvin temperatures

27th International Conference on Low Temperature Physics

Inoue, Daiki^1 ; Kaido, Daisuke^1 ; Yoshikawa, Yuta^1 ; Minegishi, Mitsuyuki^1 ; Matsumoto, Koichi^1 ; Abe, Satoshi^1

Department of Physics, Faculty of Science, Kanazawa University, Ishikawa, Kanazawa, Japan^1

关键词: Capacitance bridge;    Dilatometric measurements;    Dilution refrigerator;    Heavy fermion compounds;    Magnetostriction measurements;    Melting curve thermometers;    Millikelvin temperatures;    Quantum critical points;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/568/3/032001/pdf
DOI  :  10.1088/1742-6596/568/3/032001

来源: IOP

【 摘 要 】

We have developed a dilatometric measuring system for thermal expansion and magnetostriction, those are more singular than specific heat in approaching to a quantum critical point. With decreasing temperature, thermal expansion becomes small in proportional to the square of temperature, thus, high sensitivity and reproducibility are necessary for the dilatometric measurements in millikelvin temperatures. Our dilatometer composed of the sample and the reference capacitor provides the extremely high resolution of ΔL/L ∼ 10-10using the ratio-transformer-based capacitance bridge. The dilatometer was installed on the3He-4He dilution refrigerator with the 9 T superconducting magnet, and temperature was measured by the3He melting curve thermometer. We have measured thermal expansion and magnetostriction of the typical heavy fermion compound CeRu2Si2along a-axis at temperature down to 10 mK in magnetic fields up to 9 T.