We present low-temperature volume thermal expansion, beta, and specific heat, C, measurements on high-quality single crystals of CeNi2Ge2 YbRh2(Si0.95Ge0.05)(2) which are located very near to quantum critical points. For both systems, beta shows a more singular temperature dependence than thus the Grüneisen ratio Gamma proportional beta/C diverges as T-->0. CeNi2Ge2, our results in accordance with spin-density wave (SDW) scenario for three-dimensional spin fluctuations. By contrast, observed...

The tetragonal heavy-fermion superconductor CeRh$_{2}$As$_{2}$ with a critical temperature $T_c$ $\approx$ 0.34 K exhibits an intriguing magnetic field-induced transition between likely distinct superconducting states. In zero field, even-parity state emerges within another ordered phase of unknown origin $T_0$ 0.54 K. Here, we investigated the spin-singlet at temperatures down to 0.02$T_c$ by means local magnetization measurements performed using micro-Hall probe magnetometry. We determined...

Physical behavior of several $\mathrm{Yb}\mathrm{TM}$ intermetallics has been studied by means x-ray powder diffraction, magnetization, dc magnetic susceptibility, heat capacity, and electrical resistivity measurements. The compounds $\mathrm{Yb}T\mathrm{Bi}\mathrm{}$ with $T=\mathrm{Cu},$ Ag, Au $\mathrm{Yb}T\mathrm{Sn}$ $T=\mathrm{Ag},$ Au, Zn were shown to be nonmagnetic due the presence divalent ytterbium ions. bismuthide YbPdBi as well stannides YbRhSn YbPtSn found exhibit localized...

We have observed an unexpected enhancement of the lower critical field H(c1)(T) and current I(c)(T) deep in superconducting state below T approximately 0.6 K (T/T(c) 0.3) filled skutterudite heavy fermion superconductor PrOs(4)Sb(12). From a comparison behavior with that superconductors U(1-x)Th(x)Be(13) UPt(3), we speculate PrOs(4)Sb(12) reflects transition into another phase occurs T/T(c) 0.3. An examination literature reveals unexplained anomalies other physical properties near 0.3...

In order to elucidate the variety of correlated electron phenomena found in filled skutterudite compounds, experiments were performed on single crystals ternary Ce- and Pr-based arsenides LnT 4 As 12 (Ln = Ce, Pr; T Fe, Ru, Os) pseudoternary antimonides Pr(Os 1- x Ru ) Sb Pr Nd Os . For example, intermediate valence compound CeRu exhibits non-Fermi liquid characteristics, while compounds PrT display ferromagnetic (18 K) for BCS superconductivity (2.4 unknown (2.3 antiferromagnetic (2.2 Os....

We present low-temperature heat and charge transport as well caloric properties of a ThAsSe single crystal. An extra $\ensuremath{-}A{T}^{1/2}$ term in the electrical resistivity, independent magnetic fields high 14 T, provides evidence for an unusual scattering conduction electrons. Additionally, both thermal conductivity specific show glass-type temperature dependence which signifies presence tunneling states. These observations apparently point to experimental realization two-channel...

Single crystals of LaOs 4 As 12 , PrFe PrRu PrOs and ThFe were grown from high purity elemental specimens by mineralization in a Cd : flux. The process was carried out over 3–4 weeks sealed quartz ampoule with pressures 15–40 atm. elevated produced vapor Ar gas at the temperatures between 750–825 °C. To avoid disintegration, heated custom built pressure cell. After synthesis completed, flux components removed sublimation repeatedly used for subsequent crystallizations, thus avoiding...

Thermodynamic and transport properties of the La-diluted Kondo lattice CeNi(2)Ge(2) were studied in a wide temperature range. The Ce-rich alloys Ce(1-x)La(x)Ni(2)Ge(2) found to exhibit distinct features coherent heavy Fermi liquid. At intermediate compositions (0.7≤x≤0.9), non-Fermi liquid have been observed, followed by local behavior dilute limit. 4f-electron contribution specific heat was follow predictions Kondo-impurity model both as well regimes, with characteristic decreasing rapidly...

X-ray diffraction, electrical resistivity, magnetization, specific heat, and thermoelectric power measurements are presented for single crystals of the new filled skutterudite compound {\CeOsAs}, which reveal phenomena that associated with f - electron conduction hybridization. Valence fluctuations or Kondo behavior dominates physics down to $T$ $\sim$ 135 K. The correlated is manifested at low temperatures as a hybridization gap insulating state. small energy $Δ$$_1$/k$_B$ 73 K, taken from...

We address the origin of magnetic-field-independent $\ensuremath{-}|A|{T}^{1/2}$ term observed in low-temperature resistivity several As-based metallic systems PbFCl structure type. For layered compound ${\mathrm{ZrAs}}_{1.58}{\mathrm{Se}}_{0.39}$, we show that vacancies square nets As give rise to transport anomaly over a wide temperature regime almost two decades temperature. This behavior is line with nonmagnetic version two-channel Kondo effect, whose ascribe dynamic Jahn-Teller effect...

The ytterbium compound YbPtIn has been studied by means of single-crystal x-ray diffraction, magnetic susceptibility, magnetization, heat capacity, electrical resistivity, and magnetoresistivity measurements, performed down to 100 mK in fields up 14 T. properties are governed the presence moments ${\mathrm{Yb}}^{3+}$ ions, which order magnetically at low temperatures. Strongly enhanced electronic specific heat, highly reduced entropy, characteristic Kondo-like behavior resistivity allow...

Electrical resistivity $ρ$, specific heat C, and magnetic susceptibility $χ$ measurements made on the filled skutterudite CeRu_4As_{12} reveal non-Fermi liquid (NFL) T - dependences at low T, i.e., $ρ$(T) $\sim$ T^{1.4} weak power law or logarithmic divergences in C(T)/T $χ$(T). Measurements also show that dependence of thermoelectric S(T) deviates from seen other Ce systems. The NFL behavior appears to be associated with fluctuations valence between 3^+ 4^+ rather than a typical Kondo...

Superconducting properties of the filled skutterudite compound LaRu${}_{4}$As${}_{12}$ were investigated both as a function temperature and magnetic field. At $T\ensuremath{\ll}{T}_{\mathrm{c}}=10.45$ K, electronic contribution to specific heat was found be at variance with predictions for an $s$-wave superconductor one energy gap. In constant applied fields up ${H}_{\mathrm{c}2}(0)\ensuremath{\approx}10.2$ T, multiple gaps have been further inferred from nonlinear magnetic-field dependence...

A variety of thermodynamic and transport measurements were made on high-quality single crystals the Pr-based filled skutterudite compound ${\text{PrFe}}_{4}{\text{As}}_{12}$. Abrupt features in magnetization, ac susceptibility, specific heat, resistivity, thermoelectric power, ultrasonic velocity reveal onset long range ferromagnetic order below ${\ensuremath{\Theta}}_{C}=18\text{ }\text{K}$. The low-temperature magnetic susceptibility is characterized by a Curie--Weiss law with an effective...

Magnetization, electrical-resistivity, specific-heat, and thermopower measurements were performed on single crystals of the filled skutterudite compound ${\text{PrRu}}_{4}{\text{As}}_{12}$. These reveal a superconducting transition near 2.5 K that is quantified by: (1) magnetic susceptibility data which display an onset to Meissner state at ${T}_{c}\ensuremath{\approx}2.5\text{ }\text{K}$ complete diamagnetic shielding as $T\ensuremath{\rightarrow}2.0\text{ }\text{K}$, (2)...

Crystals of the filled skutterudite compound CeFe${}_{4}$As${}_{12}$ with three different types morphology and charge carrier concentration were grown by a molten Cd:As flux method. X-ray diffraction, magnetization, specific heat, electrical resistivity, Hall coefficient, thermoelectric power measurements on these materials, as well band structure calculations, are presented that reveal phenomena associated f-electron-conduction electron hybridization heavily doped semiconductors. Valence...

We report on the vibrational properties of lanthanum filled skutterudite compounds LaRu4Sb12, LaOs4Sb12, and LaOs4As12 studied by inelastic neutron scattering. The experimental data are backed up ab initio lattice dynamics calculations complete series skutterudites La\(T_{4}X_{12}\) with \(T\) = Fe, Ru, Os \(X\) As, Sb. present details their structural properties, phonon dispersion relations, densities states Z(ω) specific heats \(C_{V}(T)\) calculated from within harmonic approximation....

The temperature dependencies of the lower critical field ${H}_{c1}(T)$ several filled-skutterudite superconductors were investigated by local magnetization measurements. While ${\mathrm{LaOs}}_{4}{\mathrm{As}}_{12}$ and ${\mathrm{PrRu}}_{4}{\mathrm{As}}_{12}$ exhibit consistent with single-band BCS prediction, for ${\mathrm{LaRu}}_{4}{\mathrm{As}}_{12}$ (the superconducting ${T}_{c}=10.4\text{ }\text{ }\mathrm{K}$) a similar three-dimensional Fermi surface, we observe sudden increase in deep...

The temperature and magnetic field dependence of the specific heat cp(T,H) in superconducting mixed state as well upper critical Hc2(T) have been measured for polycrystalline Y_xLu_{1-x}Ni_2B_2C Y(Ni_{1-y}Pt_y)_2B_2C samples. linear-in-T electronic contribution gamma(H)T exhibits significant deviations from usual linear-in-H law all x y transition metal site (T) resulting a disorder dependent negative curvature gamma(H). that linear behaviour our unsubstituted samples are largest reported so...

We investigated low-temperature specific heat of the filled skutterudite compound LaOs4As12 with a transition temperature Tc = 3.2 K.A moderate size specific-heat jump points at weak electron-phonon coupling in this material.At T < Tc, electronic contribution to was found be variance predictions for an s-wave superconductor one energy gap.Additionally, we observed upward curvature upper critical field near temperature.Both features provide some indications towards multiband...

Temperature variation of the lower critical field ${H}_{c1}(T)$ in structurally disordered superconductor ${\mathrm{Y}}_{5}{\mathrm{Rh}}_{6}{\mathrm{Sn}}_{18}$ with a transition temperature ${T}_{c}\ensuremath{\simeq}3.2$ K was investigated using micro-Hall-probe magnetometry for local magnetization measurements. Down to about $0.45{T}_{c}$, an dependence typical single-band $s$-wave BCS observed. However, deep within superconducting state, sudden increase found, indicating presence two-band...

We report the results of low-temperature measurements specific heat ${C}_{p}(T)$, ac susceptibility ${\ensuremath{\chi}}_{\mathrm{ac}}(T)$ and $^{23}\mathrm{Na}$ nuclear magnetic resonance NMR ${\mathrm{Na}}_{2}{\mathrm{V}}_{3}{\mathrm{O}}_{7}$. At liquid He temperatures ${C}_{p}(T)$ exhibits a broad field-dependent Schottky-type anomaly. Below $1.5\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ follows Curie-Weiss law cusp at $0.086\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ which indicates phase...