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),
supported within the program of Czech Research Infrastructures (project no. LM2011025).



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


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.