Abstract
This paper reports recent progress of ultrasonic measurements on URuSi, including ultrasonic measurements under hydrostatic pressure, in pulsed magnetic fields, and the effect of Rh-substitution. The observed changes of the elastic responses shed light on the orthorhombic-lattice instability with -symmetry existing within the hidden order and the hybridized 5-electron states of URuSi.
Acknowledgements
The author would like to thank H. Saitoh, Y. Watanabe, and S. Mombetsu (Hokkaido Univ.), who contributed to the construction of the ultrasonic apparatus, and K. Hiura and T. Murazumi (Hokkaido Univ.) for helping with ultrasonic measurements. The author also thanks W. Knafo (LNCMI, Toulouse) and H. Kusunose (Ehime Univ.) for fruitful discussions. The ultrasonic measurements and sample growth done at Hokkaido University were performed in collaboration with M. Yokoyama (Ibaraki Univ.), Y. Ikeda (ISSP, Univ. of Tokyo), H. Hidaka, and H. Amitsuka (Hokkaido Univ.). Pulsed magnetic field measurements were performed in collaboration with M. Akatsu (Niigata Univ.), S. Yasin, S. Zherlitsyn, and J. Wosnitza (Helmholtz-Zentrum Dresden-Rossendorf). A single crystal used in the pulsed field measurements was grown at Univ. of California San Diego, in cooperation with M.B. Maple, K. Huang (UC San Diego) and M. Janoschek (Los Alamos Natl. Lab.). We also acknowledge the support of the Hochfeld-Magnetlabor Dresden at HZDR, a member of the European Magnetic Field Laboratory.