Specific heat and electron spin resonance of ErxLa1−xBe13

Observation of Low-Energy Einstein Phonon and Superconductivity in Single-Crystalline LaBe13

“…From the experimental results, we determined γ and θ D as 9.1 mJmol −1 K −2 and ∼ 950 K, respectively. 19) The obtained γ is in good agreement with the value determined from the two previous experiments 14,15) and a band calculation, 5) whereas the obtained θ D is somewhat higher than that reported in all the previous experimental studies. [13][14][15] The C(T )/T curve of LaBe 13 shows a broad hump anomaly near 40 K, which cannot be described only by the Debye phonon contribution.…”

“…[13][14][15] The C(T )/T curve of LaBe 13 shows a broad hump anomaly near 40 K, which cannot be described only by the Debye phonon contribution. In Fig.…”

“…In the present study, we focus our attention on LaBe 13 , since the study on a La-based compound without 4 f electrons should be essential to understand physical properties in other MBe 13 systems with f electrons. Specific-heat (C) measurements of LaBe 13 were performed and reported by three groups more than thirty years ago, where the authors estimated the electronic specific-heat coefficient γ and the Debye temperature θ D to be as follows: γ = 0.58 mJmol −1 K −2 and θ D = 820 K by Bucher et al; 13) γ =11 mJmol −1 K −2 and θ D = 554 K by Van Der Linden et al; 14) γ = 7.8 mJmol −1 K −2 and θ D = 865 K by Besnus et al 15) However, these temperature ranges in the previous studies were limited to below 40 K, and no comments about the Einstein mode were given. From electrical-resistivity (ρ) measurements, Bucher et al mentioned that a superconducting transition is absent above 0.45 K. 13) After that, Bonville et al found SC with T SC ∼ 0.27 K by the Mössbauer, ρ and dc magnetic-susceptibility measurements.…”