Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 67: Correlated Electrons: f-Electron Systems
TT 67.4: Vortrag
Mittwoch, 18. März 2015, 15:45–16:00, H 3005
Elastic Response of URu2Si2 under High Magnetic Fields — •Tatsuya Yanagisawa1, Shota Mombetsu1, Hiroyuki Hidaka1, Hiroshi Amitsuka1, Mitsuhiro Akatsu2, S. Yasin3, S. Zherlitsyn3, J. Wosnitza3, K. Huang4, M. Janoschek4, and M. B. Maple4 — 1Dept. of Physics, Hokkaido Univ., Sapporo, Japan — 2Grad. School of Science and Technology, Niigata Univ., Niigata, Japan — 3Hochfeld-Magnetlabor Dresden, Helmholtz-Zentrum Dresden-Rossendorf and TU Dresden, Dresden, Germany — 4Dept. of Physics, Univ. of California, San Diego, La Jolla, U.S.A.
We have measured the elastic constants, C44, C66, (C11−C12)/2 in URu2Si2 by means of high-frequency ultrasonic measurements in pulsed magnetic fields up to 68.7 T in a wide temperature range from 1.5 to ∼120 K. We found a reduction of (C11−C12)/2 for magnetic field H ∥ [001] that appears only in the temperature and magnetic field region in which URu2Si2 exhibits a heavy-electron state and hidden order. This change in (C11−C12)/2 appears to be a response of the 5f electrons to an orthorhombic and volume conservative strain field εxx−εyy with Γ3 symmetry. The lattice instability is likely related to a symmetry-breaking band instability that arises due to the hybridization of the localized 5f electrons with the conduction electrons and is probably linked to the hidden-order parameter of this compound. Recent progress obtained by our measurements of the transverse ultrasonic modes C44 and C66 will also be discussed.
Two of the authors (T.Y. & S.M.) are supported by the Strategic Young Researcher Overseas Visits Program for Accelerating Brain Circulation from the JSPS.