Crystal Structure and Physical Properties of Polymorphs of LnAlB<sub>4</sub> (Ln = Yb, Lu)

Macaluso, Robin T.; Nakatsuji, Satoru; Kuga, Kentaro; Thomas, E.; Machida, Yo; Maeno, Y.; Fisk, Z.; Chan, Julia Y.

doi:10.1021/cm062244+

Cited by 111 publications

(141 citation statements)

References 22 publications

Supporting

Mentioning

129

Contrasting

Order By: Relevance

“…Here we present the first empirical evidence that superconductivity is indeed possible in an ytterbium-based heavy-fermion system. In particular, we observe a superconducting transition at T c = 80 mK in high-purity single crystals of YbAlB 4 in the new structural β phase 7 . We also observe a novel type of non-Fermi-liquid state above T c that arises without chemical doping, in zero applied magnetic field and at ambient pressure, establishing β-YbAlB 4 as a unique system showing quantum criticality without external tuning.…”

mentioning

confidence: 85%

See 1 more Smart Citation

Superconductivity and quantum criticality in the heavy-fermion system β-YbAlB4

et al. 2008

View full text Add to dashboard Cite

A long-standing question in the field of superconductivity is whether pairing of electrons can arise in some cases as a result of magnetic interactions instead of electron-phonon-induced interactions as in the conventional Bardeen-Cooper-Schrieffer theory 1 . A major challenge to the idea of magnetically mediated superconductivity has been the dramatically different behaviour of the cerium and ytterbium heavy-fermion compounds. The cerium-based systems are often found to be superconducting 1-6 , in keeping with a magnetic pairing scenario, but corresponding ytterbium systems, or hole analogues of the cerium systems, are not. Despite searches over two decades there has been no evidence of heavy-fermion superconductivity in an ytterbium system, casting doubt on our understanding of the electron-hole parallelism between the cerium and the ytterbium compounds. Here we present the first empirical evidence that superconductivity is indeed possible in an ytterbium-based heavy-fermion system. In particular, we observe a superconducting transition at T c = 80 mK in high-purity single crystals of YbAlB 4 in the new structural β phase 7 . We also observe a novel type of non-Fermi-liquid state above T c that arises without chemical doping, in zero applied magnetic field and at ambient pressure, establishing β-YbAlB 4 as a unique system showing quantum criticality without external tuning.First we present the bulk magnetic and electronic properties of β-YbAlB 4 , a new morphology of the previously known α-YbAlB 4 (refs 7,8). Shown in Fig. 1a is the orthorhombic crystal structure of β-YbAlB 4 and the temperature dependence of the d.c. magnetic susceptibility χ = M/H. Here, M and H represent the magnetization and external field, respectively. The magnetic susceptibility shows the strong uniaxial anisotropy of an Ising system with moments aligned along the c axis. Above 100 K the c-axis susceptibility has a Curie-Weiss form χ c (T ) = C/(T − θ W ), with θ W ∼ −210 K and a Curie constant C corresponding to an effective Ising moment µ eff = g J J Z ∼ 3.1 µ B , where g J is the Landé g factor and J Z is the c-axis component of the total angular momentum. The in-plane susceptibility, on the other hand, is almost temperature independent, showing a weak peak around 200 K.Shown in Fig. 1b is the temperature dependence of the in-plane resistivity, ρ ab , along with the estimated 4f -electron contribution ρ m (defined in the figure caption), which shows a coherence peak at about 250 K. The low residual resistivity ρ ab (0) ∼ 0.4 µ cm and correspondingly high residual resistivity ratio, ρ ab (300 K)/ρ ab (0) ∼ 300, suggest that the electronic mean free path is of the order of 0.1 µm.In contrast to most other heavy-fermion compounds, the resistivity does not show a Fermi liquid (FL) regime characterized by a T 2 temperature variation (Fig. 1b). As shown in Fig. 1b insets, ρ ab is linear between 4 and 1 K and varies as T 1.5 below T 0 ∼ 1 K down to 80 mK. Below 80 mK our highest-purity samples are superconducting (Fig. 1b, insets). We shall...

show abstract

mentioning

confidence: 85%

“…Single crystals were grown by using the Al-flux method as described in the literature 7 . The excess Al flux was etched by a water solution of sodium hydroxide.…”

Section: Methodsmentioning

confidence: 99%

Superconductivity and quantum criticality in the heavy-fermion system β-YbAlB4

et al. 2008

View full text Add to dashboard Cite

show abstract

“…Atomic coordinates and U iso 's agree well with published values for α-YbAlB . 10 Sr 2+ has larger radius (1.26Å) than Yb 3+ (0.98Å) and Yb 2+ (1.14Å) even at high CN = 8 where the data are available for comparison which suggests that small reduction in the lattice parameters could be attributed to the increase of metallic character of Sr-B bonds 22 .…”

Section: Resultsmentioning

confidence: 95%

Multiband electronic transport inα-Yb_1−xSr_xAlB₄[x = 0, 0.19(3)] single crystals

Ryu¹,

Abeykoon²,

Božin³

et al. 2016

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

We report on the evidence for the multiband electronic transport in α-YbAlB4 and α-Yb 0.81(2) Sr 0.19(3) AlB4. Multiband transport reveals itself below 10 K in both compounds via Hall effect measurements, whereas anisotropic magnetic ground state sets in below 3 K in α-Yb 0.81(2) Sr 0.19(3) AlB4. Our results show that Sr 2+ substitution enhances conductivity, but does not change the quasiparticle mass of bands induced by heavy fermion hybridization.

show abstract

“…56 LuAlB 4 is isostructural with b-YbAlB 4 and the lanthanide atoms and Al are found between B layers. The a-and b-YbAlB 4 structures differ in the arrangement of B within the layers, although this does not have a large impact on the Yb/Al distribution in the interlayer space.…”

Section: Halides Nitrides and Intermetallicsmentioning

confidence: 95%

New compounds and structures in the solid state

Cussen

2009

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

View full text Add to dashboard Cite

This chapter reviews the 2007 literature on new compounds and structures in the solid state. HighlightsMany of the highlights of solid state chemistry that were reported in the literature during 2007 arise from studies of structures of surprising simplicity or else from astonishingly complex problems that are at the limits of the analytical techniques. A striking example of the former is the report of the binary compound ReB 2 that can be prepared by direct combination of the elements in a sealed tube. The hardness of this apparently simple material is second only to diamond. Similarly the rutile structure of TcO 2 has been described for the first time and an important chemical consideration of the effect cation doping of Zintl phases has been described. The use of topotactic modification has yielded many new mixed-metal oxides and chalcogenides of increasing complexity, with several new anion-or cation-ordering schemes being observed, as well as stabilising the remarkable perovskite-related phase SrFeO 2 . Complexity has also been a feature of both intermetallic phases and zeolites. The former are exemplified by the 433 000 Å 3 unit cell volume of a new phase in the Li/Na/Ba system whilst the latter are represented by the 24-topologically distinct Si atoms observed in the structure of the industrially-important zeolite IM-5. OxidesThe b-emitter 99 Tc is a long-lived isotope but despite a half life of 2.12 Â 10 5 years the oxide chemistry of technetium has been relatively neglected and the crystal structure of the black binary phase TcO 2 has not previously been reported. Neutron powder diffraction has been employed to complement existing X-ray absorption studies of this compound. Thus the last unknown structure of a simple transition metal oxide has been identified as possessing a distorted rutile arrangement. 1 This compound crystallises in the space group P2 1 /c with lattice parameters (a = 5.6891(1), b = 4.7546(1), c = 5.5195(1) Å and b = 121.453(1)1) in reasonable agreement with a previous indexing of X-ray diffraction data. The rarity of structural studies of technetium compounds is illustrated by necessity of improving the estimated neutron scattering length of 99 Tc from 6.8 fm to 6.00(3) fm. The distortion of the structure is largely invariant at temperatures down to 15 K and arises from Tc-Tc bonding between the edge-sharing TcO 6 octahedra in the

show abstract

Crystal Structure and Physical Properties of Polymorphs of LnAlB₄ (Ln = Yb, Lu)

Cited by 111 publications

References 22 publications

Superconductivity and quantum criticality in the heavy-fermion system β-YbAlB4

Superconductivity and quantum criticality in the heavy-fermion system β-YbAlB4

Multiband electronic transport inα-Yb_1−xSr_xAlB₄[x = 0, 0.19(3)] single crystals

New compounds and structures in the solid state

Contact Info

Product

Resources

About

Crystal Structure and Physical Properties of Polymorphs of LnAlB4 (Ln = Yb, Lu)

Cited by 111 publications

References 22 publications

Superconductivity and quantum criticality in the heavy-fermion system β-YbAlB4

Superconductivity and quantum criticality in the heavy-fermion system β-YbAlB4

Multiband electronic transport inα-Yb1−xSrxAlB4[x = 0, 0.19(3)] single crystals

New compounds and structures in the solid state

Contact Info

Product

Resources

About

Crystal Structure and Physical Properties of Polymorphs of LnAlB₄ (Ln = Yb, Lu)

Multiband electronic transport inα-Yb_1−xSr_xAlB₄[x = 0, 0.19(3)] single crystals