Tracking aluminium impurities in single crystals of the heavy-fermion superconductor UBe13

Amon, Alfred; Zelenina, Iryna; Simon, Paul; Bobnar, Matej; Naumann, M.; Svanidze, Eteri; Arnold, Frank; Borrmann, Horst; Burkhardt, Ulrich; Schnelle, Walter; Hassinger, Elena; Leithe‐Jasper, Andreas; Grin, Yuri

doi:10.1038/s41598-018-28991-w

Cited by 11 publications

(6 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…S1 – S4 . The determined lattice parameters reveal clear differences between the samples, caused most probably by Be vacancies, like it was observed for Al in the UBe Al material 53 . The possible vacancies in the Be sublattice are evident from the enhanced displacement of the Be1 and Be2 positions (Table SIIS ).…”

Section: Resultssupporting

confidence: 63%

See 1 more Smart Citation

Non-centrosymmetric superconductor Th$$_4$$Be$$_{{33}}$$Pt$$_{{16}}$$ and heavy-fermion U$$_4$$Be$$_{{33}}$$Pt$$_{{16}}$$ cage compounds

Koželj

Juckel

Amon

et al. 2021

Sci Rep

View full text Add to dashboard Cite

Unconventional superconductivity in non-centrosymmetric superconductors has attracted a considerable amount of attention. While several lanthanide-based materials have been reported previously, the number of actinide-based systems remains small. In this work, we present the discovery of a novel cubic complex non-centrosymmetric superconductor $${\text {Th}}_4{\text {Be}}_{{33}}{\text {Pt}}_{{16}}$$ Th 4 Be 33 Pt 16 ($$I{\bar{4}}3d$$ I 4 ¯ 3 d space group). This intermetallic cage compound displays superconductivity below $$T_{\text {c}} = 0.90 \pm 0.04$$ T c = 0.90 ± 0.04 K, as evidenced by specific heat and resistivity data. $${\text {Th}}_4{\text {Be}}_{{33}}{\text {Pt}}_{{16}}$$ Th 4 Be 33 Pt 16 is a type-II superconductor, which has an upper critical field $${\text {H}}_{{\text {c}}2} = 0.27$$ H c 2 = 0.27 T and a moderate Sommerfeld coefficient $$\gamma _{\text {n}} = 16.3 \pm 0.8$$ γ n = 16.3 ± 0.8 mJ $${\text {mol}}^{-1}_{\text {Th}}$$ mol Th - 1 $${\text {K}}^{-2}$$ K - 2 . A non-zero density of states at the Fermi level is evident from metallic behavior in the normal state, as well as from electronic band structure calculations. The isostructural $${\text {U}}_4{\text {Be}}_{{33}}{\text {Pt}}_{{16}}$$ U 4 Be 33 Pt 16 compound is a paramagnet with a moderately enhanced electronic mass, as indicated by the electronic specific heat coefficient $$\gamma _{\text {n}} = 200$$ γ n = 200 mJ $${\text {mol}}^{-1}_{\text {U}}$$ mol U - 1 $${\text {K}}^{-2}$$ K - 2 and Kadowaki–Woods ratio $$A/\gamma ^2 = 1.1 \times 10^{-5}$$ A / γ 2 = 1.1 × 10 - 5 $$\upmu $$ μ $$\Omega $$ Ω cm $${\text {K}}^2$$ K 2 $${\text {mol}}_{\text {U}}^2$$ mol U 2 (mJ)$$^{-2}$$ - 2 . Both $${\text {Th}}_4{\text {Be}}_{{33}}{\text {Pt}}_{{16}}$$ Th 4 Be 33 Pt 16 and $${\text {U}}_4{\text {Be}}_{{33}}{\text {Pt}}_{{16}}$$ U 4 Be 33 Pt 16 are crystallographically complex, each hosting 212 atoms per unit cell.

show abstract

Section: Resultssupporting

confidence: 63%

“…The effective mass enhancement in the U Be Pt compound is less than that, observed in unconventional superconductor UBe 50 – 52 —another heavy-fermion system containing Be and U. What both compounds have in common is a very strong coupling between minute changes in crystal chemistry and resultant physical properties 53 .…”

Section: Introductionmentioning

confidence: 85%

Non-centrosymmetric superconductor Th$$_4$$Be$$_{{33}}$$Pt$$_{{16}}$$ and heavy-fermion U$$_4$$Be$$_{{33}}$$Pt$$_{{16}}$$ cage compounds

Koželj

Juckel

Amon

et al. 2021

Sci Rep

View full text Add to dashboard Cite

show abstract

“…It was possible to only detect the signals of Sm, B and O, with Gd being below the detection limit (usually ∼ 1 %) [47]. Interestingly, after milling no Al signal could be detected, indicating that the Al content in the bulk, if any, is below the detection limit -which differs from, e.g., UBe 13 [66].…”

Section: Methodsmentioning

confidence: 99%

Surface excitations relaxation in the Kondo insulator Sm$_{1-x}$Gd$_{x}$B$_{6}$

Souza,

König,

Crivillero

et al. 2021

Preprint

View full text Add to dashboard Cite

The interplay between non-trivial topological states of matter and strong electronic correlations is one of the most compelling open questions in condensed matter physics. Due to experimental challenges, there is an increasing desire to find more microscopic techniques to complement the results of more traditional experiments. In this work, we locally explore the Kondo insulator Sm1−xGdxB6 by means of electron spin resonance (ESR) of Gd 3+ ions at low temperatures. Our analysis reveals that the Gd 3+ ESR line shape shows an anomalous evolution as a function of temperature, wherein for highly dilute samples (x ≈ 0.0002) the Gd 3+ ESR line shape changes from a localized ESR local moment character to a diffusive-like character. Upon manipulating the sample surface with a focused ion beam we demonstrate, in combination with electrical resistivity measurements, that the localized character of the Gd 3+ ESR line shape is recovered by increasing the penetration of the microwave in the sample. This provides compelling evidence for the contribution of surface or near-surface excitations to the relaxation mechanism in the Gd 3+ spin dynamics. Our work brings new insights into the importance of non-trivial surface excitations in ESR, opening new routes to be explored both theoretically and experimentally.

show abstract

“…This unintentional doping is at least a partial reason for the degradation in properties (lower Tc, higher residual 0) between the single crystal and the polycrystalline sample of undoped UBe13 shown in Table 2. A more thorough characterization by Amon et al [48] of the effect of intentionally added Al in polycrystalline UBe13 found that Al is soluble in UBe13, and substitutes for Be, up to approximately x=0.3 (i. e. up to UBe12.7Al0.3). A further aspect of this work is a study [48] of the annealing effects at 900 o C up to 2 ½ months of the specific heat of single crystals grown in Al flux.…”

Section: X=0mentioning

confidence: 99%

“…A more thorough characterization by Amon et al [48] of the effect of intentionally added Al in polycrystalline UBe13 found that Al is soluble in UBe13, and substitutes for Be, up to approximately x=0.3 (i. e. up to UBe12.7Al0.3). A further aspect of this work is a study [48] of the annealing effects at 900 o C up to 2 ½ months of the specific heat of single crystals grown in Al flux.…”

Section: X=0mentioning

confidence: 99%

UBe13 and U1−xThxBe13: Unconventional Superconductors

Stewart

2019

J Low Temp Phys

View full text Add to dashboard Cite

UBe13 was the second discovered heavy fermion superconductor, and numerous pieces of evidence exist that imply that it is an unconventional (non-BCS swave) superconductor. Exhibiting even more signs of unconventional superconductivity, Th-doped UBe13 is perhaps the most puzzling of any of the unconventional superconductors. This review considers both the parent, undoped compound as well as the more interesting U1-xThxBe13. After summarizing the rather thorough characterization -which because of the interest in these compounds, has continued from their discovery in 1983 and 1984 to date -these properties are compared with a recent 'template' for determining whether a superconductor is unconventional. Finally, further experiments are suggested. II A. Normal State Experimental Results for UBe13/U1-xThxBe13

show abstract

Tracking aluminium impurities in single crystals of the heavy-fermion superconductor UBe13

Cited by 11 publications

References 62 publications

Non-centrosymmetric superconductor Th$$_4$$Be$$_{{33}}$$Pt$$_{{16}}$$ and heavy-fermion U$$_4$$Be$$_{{33}}$$Pt$$_{{16}}$$ cage compounds

Non-centrosymmetric superconductor Th$$_4$$Be$$_{{33}}$$Pt$$_{{16}}$$ and heavy-fermion U$$_4$$Be$$_{{33}}$$Pt$$_{{16}}$$ cage compounds

Surface excitations relaxation in the Kondo insulator Sm$_{1-x}$Gd$_{x}$B$_{6}$

UBe13 and U1−xThxBe13: Unconventional Superconductors

Contact Info

Product

Resources

About