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Title: Naoyuki Miura: Anomalous metallic state in Th1-xUxBe13 (0‹x‹1)
Number: 43/15
Status: Closing date exceeded
Begin: Wednesday, 02.12. 2015, 14:50
Location: lecture room F2, first floor Ke Karlovu 5


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 We have a pleasure to invite you to attend the joint seminar
of the Department of Condensed Matter Physics (DCMP)
and the Magnetism and Low Temperature Laboratories (MLTL) http://mltl.eu,
supported within the program of Czech Research Infrastructures (project no. LM2011025).

 

Program

Anomalous metallic state in Th1-xUxBe13 (0‹x‹1)

  

lecture given by:

Naoyuki Miura

Hokkaido University & DCMP

The seminar takes place in the lecture room F2
of the Faculty of Mathematics and Physics, Ke Karlovu 5, Praha 2
on Wednesday, 2.12.2015 from 14:50 

Vladimír Sechovský
On behalf of the DCMP and MLTL


Abstract 

The first and still central U-based heavy-fermion superconductor, UBe13 (Tc ~ 0.8 K, g ~1000 mJmol-1K-2),  is the main topic of my talk. This compound exhibits anomalous “Non-Fermi-liquid” (NFL) state above TC, whose origin could be crucial to understand the unconventional superconductivity of this system. Our previous studies on the diluted magnetic system Th1-xUxBe13 (x £ 0.11) revealed that the low-temperature properties in the dilute U limit is described as Fermi liquid (FL), and imply that the anomalous NFL state in the pure UBe13 could be attributed to a quantum criticality due to the competition between the crystalline-electric-field singlet state versus the Kondo-Yosida singlet state. In order to see how the low-temperature state changes from FL to NFL with x, we have performed magnetic susceptibility (c), specific heat (C), and electric resistivity (r) measurements on the Th1-xUxBe13 single crystals in the whole range of U concentration 0 £ x £ 1 in Charles University, Prague. The obtained Weiss temperature is negative for the whole range of x and its absolute value increases with increasing x. The electronic specific-heat coefficient at low temperature also increases monotonically with increasing x. Interestingly, the characteristic temperature of the Fermi-liquid state estimated from C(T) and c(T) decreases continuously and monotonically with increasing x, and vanishes above x* ~ 0.8, where the NFL behavior becomes obvious in C/T and r. These results strongly suggest that a crossover of the low-T state between FL and NFL occurs around x*.In the present talk, I would like to discuss the origin of the anomalous metallic state in UBe13 from the aspect of the x variations of single U-site effects, U-U intersite correlations, lattice parameter, and so on.